Optical Transducer Research Articles

Lightning Current Measurement Form and Arrangement Scheme of Transmission Line Based on Point-Type Optical Current Transducer.

Lightning strikes are the main cause of transmission line faults, and the accurate lightning current number is an important basis to guide scientific lightning protection. The use of sensors with excellent sensing performance to carry out lightning current monitoring on transmission lines is beneficial to the accumulation of key parameters of original lightning strikes, so it is necessary to study the lightning current measurement structure of transmission lines. In this paper, an optical current-sensing unit is used to monitor the lightning current on transmission lines. A measuring structure that can monitor key parameters of the lightning current under different types of lightning strikes is proposed. First, establish the lightning current return channel model and the equivalent model of the tower, study the influence of the transmission tower on the current in the lightning channel, and analyze the direct measurement position of the lightning current on the tower; establish the multi-wave impedance model of the tower, and build a multi-base tower. The simulation model of the transmission system analyzes the transmission characteristics of the lightning current on the transmission line and the lightning protection line in the case of different types of faults; from the perspective of the measurement of key parameters of the lightning current, the lightning current measurement structure of the transmission system is constructed to analyze different lightning strikes. The measurement effect of each monitoring position in the case of a lightning strike and the waveform characteristics of the fault current in the case of insulator flashover are analyzed.

(Invited) Melanin-Inspired Functionalization of Single-Walled Carbon Nanotubes for Optical Detection of Metals

The accumulation of metal ions in organisms and the presence of heavy metals in water cause adverse effects on ecosystems and result in numerous human health issues such as cancer and neurogenerative diseases. Therefore, the development of novel platforms for metal-scavenging and rapid metal detection for in situ applications are of high importance. Here, this challenge is tackled by taking advantage of the metal chelation ability of a melanin-inspired material in combination with the near-infrared (NIR) fluorescence response of single-walled carbon nanotubes (SWCNTs) to surface binding. SWCNTs are functionalized by a melanin-like substance, obtained by enzymatic oxidative polymerization of a fluorenylmethyloxycarbonyl-tyrosine (FmocY) precursor. The resulting multicomponent system (SWCNT-FmocYOx) serves as a metal-ion scavenging platform that concurrently reports on metal binding with optical signal transduction. Upon binding of a library of mostly divalent transition metal-ions, the fluorescence emission of the functionalized SWCNTs is modulated, showing a concentration-dependent response with a limit of detection in the nanomolar range. Metal-binding and removal from water of up to 98% are further shown via inductively coupled plasma mass spectrometry. The SWCNT-FmocYOx hybrid system presents a novel platform with NIR optical signal for real-time feedback on metal-ion scavenging.

A Combined Plasmonic and Electrochemical Aptasensor Based on Gold Nanopit Arrays for the Detection of Human Serum Albumin.

Electrochemical and optical platforms are commonly employed in designing biosensors. However, one signal readout can easily lead to inaccuracies due to the effect of nonstandard test procedures, different operators, and experimental environments. We have developed a dual-signal protocol that combined two transducer principles in one aptamer-based biosensor by simultaneously performing electrochemical- and extraordinary optical transmission (EOT)-based plasmonic detection using gold nanopit arrays (AuNpA). Compared with full hole structures, we found that nanopits, that did not fully penetrate the gold film, not only exhibited a better plasmonic bandwidth and refractive index sensitivity both in the finite-difference time-domain simulation and in experiments by shielding the gold/quartz mode but also enlarged the electrochemical active surface area. Therefore, the periodic non-fully penetrating AuNpA were modified with ferrocene-labeled human serum albumin aptamer receptors. The formation of the receptor layer and human serum albumin binding complex induced a conformational change, which resulted in variation in the electron transfer between the electro-active ferrocene units and the AuNpA surface. Simultaneously, the binding event caused a surface plasmon polaritons wavelength shift corresponding to a change in the surface refractive index. Interestingly, although both transducers recorded the same binding process, they led to different limits of detection, dynamic ranges, and sensitivities. The electrochemical transducer showed a dynamic detection range from 1 nM to 600 μM, while the optical transducer covered high concentrations from 100 μM to 600 μM. This study not only provides new insights into the design of plasmonic nanostructures but also potentially opens an exciting avenue for dual-signal disease diagnosis and point-of-care testing applications.

Sensitive Escherichia coli detection using porous Si immunosensor coupled with rapid catalytic signal amplification

Rapid, facile and sensitive detection of water-borne pollutants is crucial to safeguarding public health. Herein, a miniaturized biosensing platform based on a porous silicon (p-Si) interferometer was designed to detect Escherichia coli (E. coli) contamination in a rapid and reliable manner. An indirect immunoassay followed by simple syringe filtration was adapted to exclude the unreacted antibodies tagged with horseradish peroxidase (HRP) from the bacterial suspension, while the optical transducer assessed the residual immuno-entities. Quantification of minute E. coli concentrations was achieved by the HRP moieties' biochemical activation and real-time monitoring of the reaction products' infiltration into the porous nanostructure by alternating reflectance spectra. The developed bioassay depicted high sensitivity against target microorganism detection, as low as 2 CFU mL−1, with a linear response of 101 ̶ 105 CFU mL−1. Furthermore, the selectivity was tested using the common interfering pathogens, Listeria monocytogenes, Salmonella enterica serovar Typhimurium, Staphylococcus aureus, Staphylococcus epidermidis and Bacillus cereus, resulting in satisfactory output. Finally, the potential applicability of the developed platform for real-life scenarios was interpreted with respect to the standard culture plate approach while depicting recovery values of 92 ̶ 107 % in ground, irrigation and river water, as well as in staple food samples (raw and pasteurized milk). Overall, the miniaturized p-Si scaffold can be utilized for various emerging applications with pathogenesis-relevant assessments conducted under on-site conditions.

Ammonia and Humidity Sensing by Phthalocyanine-Corrole Complex Heterostructure Devices.

The versatility of metal complexes of corroles has raised interest in the use of these molecules as elements of chemical sensors. The tuning of the macrocycle properties via synthetic modification of the different components of the corrole ring, such as functional groups, the molecular skeleton, and coordinated metal, allows for the creation of a vast library of corrole-based sensors. However, the scarce conductivity of most of the aggregates of corroles limits the development of simple conductometric sensors and requires the use of optical or mass transducers that are rather more cumbersome and less prone to be integrated into microelectronics systems. To compensate for the scarce conductivity, corroles are often used to functionalize the surface of conductive materials such as graphene oxide, carbon nanotubes, or conductive polymers. Alternatively, they can be incorporated into heterojunction devices where they are interfaced with a conductive material such as a phthalocyanine. Herewith, we introduce two heterostructure sensors combining lutetium bisphthalocyanine (LuPc2) with either 5,10,15-tris(pentafluorophenyl) corrolato Cu (1) or 5,10,15-tris(4-methoxyphenyl)corrolato Cu (2). The optical spectra show that after deposition, corroles maintain their original structure. The conductivity of the devices reveals an energy barrier for interfacial charge transport for 1/LuPc2, which is a heterojunction device. On the contrary, only ohmic contacts are observed in the 2/LuPc2 device. These different electrical properties, which result from the different electron-withdrawing or -donating substituents on corrole rings, are also manifested by the opposite response with respect to ammonia (NH3), with 1/LuPc2 behaving as an n-type conductor and 2/LuPC2 behaving as a p-type conductor. Both devices are capable of detecting NH3 down to 10 ppm at room temperature. Furthermore, the sensors show high sensitivity with respect to relative humidity (RH) but with a reversible and fast response in the range of 30-60% RH.

Conjugated Polymers for Aptasensing Applications.

Rapid and specific assaying of molecules that report on a pathophysiological condition, environmental pollution, or drug concentration is pivotal for establishing efficient and accurate diagnostic systems. One of the main components required for the construction of these systems is the recognition element (receptor) that can identify target analytes. Oligonucleotide switching structures, or aptamers, have been widely studied as selective receptors that can precisely identify targets in different analyzed matrices with minimal interference from other components in an antibody-like recognition process. These aptasensors, especially when integrated into sensing platforms, enable a multitude of sensors that can outperform antibody-based sensors in terms of flexibility of the sensing strategy and ease of deployment to areas with limited resources. Research into compounds that efficiently enhance signal transduction and provide a suitable platform for conjugating aptamers has gained huge momentum over the past decade. The multifaceted nature of conjugated polymers (CPs), notably their versatile electrical and optical properties, endows them with a broad range of potential applications in optical, electrical, and electrochemical signal transduction. Despite the substantial body of research demonstrating the enhanced performance of sensing devices using doped or nanostructure-embedded CPs, few reviews are available that specifically describe the use of conjugated polymers in aptasensing. The purpose of this review is to bridge this gap and provide a comprehensive description of a variety of CPs, from a historical viewpoint, underpinning their specific characteristics and demonstrating the advances in biosensors associated with the use of these conjugated polymers.

Responsive Janus droplets as modular sensory layers for the optical detection of bacteria

The field of biosensor development is fueled by innovations in new functional transduction materials and technologies. Material innovations promise to extend current sensor hardware limitations, reduce analysis costs, and ensure broad application of sensor methods. Optical sensors are particularly attractive because they enable sensitive and noninvasive analyte detection in near real-time. Optical transducers convert physical, chemical, or biological events into detectable changes in fluorescence, refractive index, or spectroscopic shifts. Thus, in addition to sophisticated biochemical selector designs, smart transducers can improve signal transmission and amplification, thereby greatly facilitating the practical applicability of biosensors, which, to date, is often hampered by complications such as difficult replication of reproducible selector-analyte interactions within a uniform and consistent sensing area. In this context, stimuli-responsive and optically active Janus emulsions, which are dispersions of kinetically stabilized biphasic fluid droplets, have emerged as a novel triggerable material platform that provides as a versatile and cost-effective alternative for the generation of reproducible, highly sensitive, and modular optical sensing layers. The intrinsic and unprecedented chemical-morphological-optical coupling inside Janus droplets has facilitated optical signal transduction and amplification in various chemo- and biosensor paradigms, which include examples for the rapid and cost-effective detection of major foodborne pathogens. These initial demonstrations resulted in detection limits that rival the capabilities of current commercial platforms. This trend article aims to present a conceptual summary of these initial efforts and to provide a concise and comprehensive overview of the pivotal kinetic and thermodynamic principles that govern the ability of Janus droplets to sensitively and selectively respond to and interact with bacteria.Graphical abstract

Microbubble Resonators for Photoacoustic Detection and Photothermal Spectroscopy

Optical microresonators based on Whispering Gallery Modes have been extensively investigated as unique tools for fundamental studies and as core components in several applications. Specifically, microbubbles resonators (MBR) made from glass capillaries combine high optical and mechanical Q-factors together with intrinsic microfluidics, and in this work we demonstrate them as unique platforms for photoacoustic (PA) detection and photothermal (PT) spectroscopy. In a first configuration, we employed a MBR as an optical transducer to detect the PA signal generated by a suspension of gold nanorods (GNRs) placed within the MBR, demonstrating all-optical PA detection and high sensitivity towards nanoparticles optical absorption. The MBR acts both as the ultrasound sensor and as the microvial, enabling the inspection of submicroliter samples without the need for impedance-matching media. We then present a flow cytometry experiment where the GNRs run through the MBR, and we estimate PA intensity by a Fourier analysis of the read-out signal. The sharp MBR mechanical eigenmodes allowed to easily decouple the environmental noise from the PA contributions. In a second proof-of-concept experiment using a similar setup, we implemented the MBR transducer to reconstruct the GNRs absorption spectrum through the photothermal conversion. The high sensitivity of the MBR towards temperature variations allowed for the interrogation of small samples while using a low-intensity beam for their excitation. This thermal detection produces spectra that are insensitive towards light scattering in the sample, as proved experimentally by comparing the spectra of aqueous GNR suspensions in the presence or absence of milk powder.

Intensity-Based Camera Setup for Refractometric and Biomolecular Sensing with a Photonic Crystal Microfluidic Chip.

Label-free sensing is a promising approach for point-of-care testing devices. Among optical transducers, photonic crystal slabs (PCSs) have positioned themselves as an inexpensive yet versatile platform for label-free biosensing. A spectral resonance shift is observed upon biomolecular binding to the functionalized surface. Commonly, a PCS is read out by a spectrometer. Alternatively, the spectral shift may be translated into an intensity change by tailoring the system response. Intensity-based camera setups (IBCS) are of interest as they mitigate the need for postprocessing, enable spatial sampling, and have moderate hardware requirements. However, they exhibit modest performance compared with spectrometric approaches. Here, we show an increase of the sensitivity and limit of detection (LOD) of an IBCS by employing a sharp-edged cut-off filter to optimize the system response. We report an increase of the LOD from (7.1 ± 1.3) × 10-4 RIU to (3.2 ± 0.7) × 10-5 RIU. We discuss the influence of the region of interest (ROI) size on the achievable LOD. We fabricated a biochip by combining a microfluidic and a PCS and demonstrated autonomous transport. We analyzed the performance via refractive index steps and the biosensing ability via diluted glutathione S-transferase (GST) antibodies (1:250). In addition, we illustrate the speed of detection and demonstrate the advantage of the additional spatial information by detecting streptavidin (2.9 µg/mL). Finally, we present the detection of immunoglobulin G (IgG) from whole blood as a possible basis for point-of-care devices.

Carbon dot/Co-MOF nanocoral mediated fluorescence-scattering ratiometric sensor for highly sensitive detection of alkaline phosphatase

Abnormal expression of alkaline phosphatase (ALP) in serum has received considerable attention in health monitoring and disease diagnosis. However, conventional optical analysis based on a single signal must compromise background interference and limited sensitivity in trace analysis. As an alternative candidate, the ratiometric approach depends on the self-calibration of two independent signals in a single test to minimize interferences from the background for accurate identification. Here, a carbon dot/cobalt-metal organic framework nanocoral (CD/Co-MOF NC) mediated fluorescence-scattering ratiometric sensor has been developed for simple, stable, and highly sensitive detection of ALP. ALP-responsive phosphate production was used to coordinate cobalt ion and collapse the CD/Co-MOF NC, resulting in the recovery of fluorescence signal from dissociative CDs and the decrease of second-order scattering (SOS) signal from the cracked CD/Co-MOF NC. The ligand-substituted reaction and the optical ratiometric signal transduction provide a rapid and reliable chemical sensing mechanism. The ratiometric sensor effectively converted ALP into a ratio signal of fluorescence-scattering dual emission throughout a wide linear concentration range of six orders of magnitude with a detection limit of 0.6 mU/L. In addition, self-calibration of fluorescence-scattering ratiometric method can reduce background interference and improve sensitivity in serum, approaching recoveries of ALP from 98.4% to 101.8%. Due to the above advantages, the CD/Co-MOF NC mediated fluorescence-scattering ratiometric sensor readily provides rapid and stable quantitative detection of ALP as a promising in vitro analytical method for clinical diagnostics.

The Development of Optomechanical Sensors—Integrating Diffractive Optical Structures for Enhanced Sensitivity

The term optomechanical sensors describes devices based on coupling the optical and mechanical sensing principles. The presence of a target analyte leads to a mechanical change, which, in turn, determines an alteration in the light propagation. Having higher sensitivity in comparison with the individual technologies upon which they are based, the optomechanical devices are used in biosensing, humidity, temperature, and gases detection. This perspective focuses on a particular class, namely on devices based on diffractive optical structures (DOS). Many configurations have been developed, including cantilever- and MEMS-type devices, fiber Bragg grating sensors, and cavity optomechanical sensing devices. These state-of-the-art sensors operate on the principle of a mechanical transducer coupled with a diffractive element resulting in a variation in the intensity or wavelength of the diffracted light in the presence of the target analyte. Therefore, as DOS can further enhance the sensitivity and selectivity, we present the individual mechanical and optical transducing methods and demonstrate how the DOS introduction can lead to an enhanced sensitivity and selectivity. Their (low-) cost manufacturing and their integration in new sensing platforms with great adaptability across many sensing areas are discussed, being foreseen that their implementation on wider application areas will further increase.

Spatially Resolved Protein Binding Kinetics Analysis in Microfluidic Photonic Crystal Sensors

Organ-on-a-Chip systems are emerging as an important in vitro analysis method for drug screening and medical research. For continuous biomolecular monitoring of the cell culture response, label-free detection within the microfluidic system or in the drainage tube is promising. We study photonic crystal slabs integrated with a microfluidic chip as an optical transducer for label-free biomarker detection with a non-contact readout of binding kinetics. This work analyzes the capability of same-channel reference for protein binding measurements by using a spectrometer and 1D spatially resolved data evaluation with a spatial resolution of 1.2 μm. A cross-correlation-based data-analysis procedure is implemented. First, an ethanol–water dilution series is used to obtain the limit of detection (LOD). The median of all row LODs is (2.3±0.4)×10−4 RIU with 10 s exposure time per image and (1.3±0.24)×10−4 RIU with 30 s exposure time. Next, we used a streptavidin–biotin binding process as a test system for binding kinetics. Time series of optical spectra were recorded while constantly injecting streptavidin in DPBS at concentrations of 1.6 nM, 3.3 nM, 16.6 nM and 33.3 nM into one channel half as well as the whole channel. The results show that localized binding within a microfluidic channel is achieved under laminar flow. Furthermore, binding kinetics are fading out at the microfluidic channel edge due to the velocity profile.

Development of Optical Label-Free Biosensor Method in Detection of Listeria monocytogenes from Food.

The present work describes an alternative method for detecting and identifying Listeria monocytogenes in food samples by developing a nanophotonic biosensor containing bioreceptors and optical transducers. The development of photonic sensors for the detection of pathogens in the food industry involves the implementation of procedures for selecting probes against the antigens of interest and the functionalization of the sensor surfaces on which the said bioreceptors are located. As a previous step to functionalizing the biosensor, an immobilization control of these antibodies on silicon nitride surfaces was carried out to check the effectiveness of in plane immobilization. On the one hand, it was observed that a Listeria monocytogenes-specific polyclonal antibody has a greater binding capacity to the antigen at a wide range of concentrations. A Listeria monocytogenes monoclonal antibody is more specific and has a greater binding capacity only at low concentrations. An assay for evaluating selected antibodies against particular antigens of Listeria monocytogenes bacteria was designed to determine the binding specificity of each probe using the indirect ELISA detection technique. In addition, a validation method was established against the reference method for many replicates belonging to different batches of meat-detectable samples, with a medium and pre-enrichment time that allowed optimal recovery of the target microorganism. Moreover, no cross-reactivity with other nontarget bacteria was observed. Thus, this system is a simple, highly sensitive, and accurate platform for L. monocytogenes detection.

Looking into the ion-selective nanoptode bulk – Alternative mechanism of optical signal transduction for ratiometric ion-selective probes applicable in broad pH range

Ion-selective sensors, including optodes, explore ion-exchange at the interface to observe analyte ion binding to neutral ionophore in the probe bulk. Typically the optical transducer used is a charged dye - incorporation of analyte cation requires expulsion of positively charged ion from the probe, the process is giving rise to observable optical signal. We propose an alternative approach focused on the probe bulk and allowing application of uncharged dye as the optical transducer. The neutral solvatochromic dye is not involved in maintaining electroneutrality, but its optical spectrum reflects local changes occurring in the probe bulk in response to analyte incorporation, giving rise to analytical signal dependent on the analyte concentration changes in the sample. The proposed optical transduction mechanism offers increase of emission for increase of analyte contents in the sample in a broad concentration range, a linear dependence of optical signal on logarithm of concentration was observed. Moreover, this approach results in significant benefits: it mitigates the cross sensitivity to hydrogen ions concentration changes observed for classical optodes, allowing application of probes in unbuffered samples as well as in wide pH range, including acidic solution. The system requires the presence of adjunctive, cationic species in the probe, that are exchanged for analyte cations preferred in the system due to interactions with ionophore. Depending on the choice of adjunctive cation ratiometric sensing can be achieved. It is also shown that such system does not require the presence of a surfactant, yet allows formation of stable emulsion of nanoprobes.

(Bio-)Sensors for skin grafts and skin flaps monitoring

Skin grafting is one of the most frequently performed surgical procedures in dermatology. Nevertheless, the failure rate is still quite high, which can cause a huge burden for patients and the health care system. Early interventions, like salvage surgery, can rescue the grafts that are going to fail. Therefore, real-time and objective monitoring of skin grafts and flaps is crucial to guide clinicians for an evidence-based treatment. This can be achieved by modern sensor applications using advanced techniques in nanotechnology and material science. This review provides an overview on current challenges for the further development of (bio-)sensors for monitoring the uptake of implanted skin grafts and skin flaps. Special interest has been given to invasive/non-invasive as well as wearable/implantable applications. In addition, the adaptation of recent developments in alternative sensing systems with physical, optical and electrochemical transducers for the continuous monitoring (intra- and post-operative) of skin transplants has been discussed.

Near-field enhancement of optical second harmonic generation in hybrid gold–lithium niobate nanostructures

Nanophotonics research has focused recently on the ability of nonlinear optical processes to mediate and transform optical signals in a myriad of novel devices, including optical modulators, transducers, color filters, photodetectors, photon sources, and ultrafast optical switches. The inherent weakness of optical nonlinearities at smaller scales has, however, hindered the realization of efficient miniaturized devices, and strategies for enhancing both device efficiencies and synthesis throughput via nanoengineering remain limited. Here, we demonstrate a novel mechanism by which second harmonic generation, a prototypical nonlinear optical phenomenon, from individual lithium niobate particles can be significantly enhanced through nonradiative coupling to the localized surface plasmon resonances of embedded gold nanoparticles. A joint experimental and theoretical investigation of single mesoporous lithium niobate particles coated with a dispersed layer of ~10 nm diameter gold nanoparticles shows that a ~32-fold enhancement of second harmonic generation can be achieved without introducing finely tailored radiative nanoantennas to mediate photon transfer to or from the nonlinear material. This work highlights the limitations of current strategies for enhancing nonlinear optical phenomena and proposes a route through which a new class of subwavelength nonlinear optical platforms can be designed to maximize nonlinear efficiencies through near-field energy exchange.

Anti-crosstalk magnetic field method for straight-light path type optical current transducer based on the background of gas-insulated substation

Anti-crosstalk magnetic field method for straight-light path type optical current transducer based on the background of gas-insulated substation

Robust Rules for Optimal Colorimetric Sensing Based on Gold Nanoparticle Aggregation.

Spurred by outstanding optical properties, chemical stability, and facile bioconjugation, plasmonic metals have become the first-choice materials for optical signal transducers in biosensing. While the design rules for surface-based plasmonic sensors are well-established and commercialized, there is limited knowledge of the design of sensors based on nanoparticle aggregation. The reason is the lack of control over the interparticle distances, number of nanoparticles per cluster, or multiple mutual orientations during aggregation events, blurring the threshold between positive and negative readout. Here we identify the geometrical parameters (size, shape, and interparticle distance) that allow for maximizing the color difference upon nanoparticle clustering. Finding the optimal structural parameters will provide a fast and reliable means of readout, including unaided eye inspection or computer vision.

Theoretical analysis of putrescine enzymatic biosensor with optical oxygen transducer in sensitive layer using Akbari–Ganji method

This article reports a theoretical analysis of the reaction-transport processes of the Putrescine enzymatic biosensor inside the sensitive layer under steady-state conditions. It consists of two substrates with the same reaction rate and depends on non-linear reaction-diffusion equations. A simple approximate analytical expression for the concentration of substrates (Putrescine and Oxygen) and current are obtained analytically using the Akbari-Ganji and homotopy analysis method. Further, the resistance and sensitivity of a biosensor are also determined using the current. The numerical simulation of the problem is presented in this study using the Matlab program. Comparing analytical results with simulation results for the experimental parameter values has shown satisfactory agreement. Also, the effect of the parameters on current is investigated using sensitivity analysis. The most crucial factor affecting current is the sensing layer's oxygen concentration, followed by the kinetics and transport parameters. However, the reciprocal of the square of the Thiele modulus and the putrescine concentration in the sensing layer has the most negligible impact. Our obtained results are useful in optimizing and designing biosensors.

Quantum-enabled millimetre wave to optical transduction using neutral atoms.

Early experiments with transiting circular Rydberg atoms in a superconducting resonator laid the foundations of modern cavity and circuit quantum electrodynamics1, and helped explore the defining features of quantum mechanics such as entanglement. Whereas ultracold atoms and superconducting circuits have since taken rather independent paths in the exploration of new physics, taking advantage of their complementary strengths in an integrated system enables access to fundamentally new parameter regimes and device capabilities2,3. Here we report on such a system, coupling an ensemble of cold 85Rb atoms simultaneously to an, as far as we are aware, first-of-its-kind optically accessible, three-dimensional superconducting resonator4 and a vibration-suppressed optical cavity in a cryogenic (5 K) environment. To demonstrate the capabilities of this platform, and with an eye towards quantum networking5, we leverage the strong coupling between Rydberg atoms and the superconducting resonator to implement a quantum-enabled millimetre wave (mmwave) photon to optical photon transducer6. We measured an internal conversion efficiency of 58(11)%, a conversion bandwidth of 360(20) kHz and added thermal noise of 0.6 photons, in agreement with a parameter-free theory. Extensions of this technique will allow near-unity efficiency transduction in both the mmwave and microwave regimes. More broadly, our results open a new field of hybrid mmwave/optical quantum science, with prospects for operation deep in the strong coupling regime for efficient generation of metrologically or computationally useful entangled states7 and quantum simulation/computation with strong non-local interactions8.