Solid-state Sources Research Articles

Area theorem for coherent pulse propagation in a quantum-dot laser.

We extend the area theorem toward the analytical description of the coherent pulse propagation in a quantum-dot (QD) laser medium in a ring-cavity setup. We apply the derived area theorem to demonstrate the appearance of the stable coherent mode-locking regime in a single-section ring-cavity QD laser. The paper findings showcase the possibility of making compact solid-state sources of ultrashort pulses with pulse duration well beyond the gain bandwidth limit.

LED-based optoacoustic tomography of mice.

Optoacoustic tomography systems commonly employ bulky and expensive solid-state laser sources readily capable of generating dozens of millijoules of optical energy per pulse. Light-emitting diodes (LEDs) may offer a significantly more affordable and compact solution with excellent pulse-to-pulse stability. Yet, the optical design must optimize the energy density delivered to the target, given the relatively low per-pulse energy output of LEDs. We exploit a full-view LED-based optoacoustic tomography (FLOAT) configuration for in vivo imaging of mice. The system features panoramic light illumination delivering 0.48 mJ of total per-pulse energy with an array of 160 LEDs stacked into a cylindrically focused circular ultrasound array transducer. We characterize the imaging performance of the FLOAT system in tissue-mimicking phantoms, subsequently demonstrating its ability for in vivo cross-sectional mouse imaging. It is anticipated that the compact, low-cost FLOAT imaging system will open up new venues in resource-limited settings for studying large-scale biodynamics such as pharmacokinetics and biodistribution of molecular agents and drugs on a whole-body level.

Speckle suppression by a hybrid dual solid-state light source in laser projection

Laser projection has become a new trend in display technology. However, speckle noise due to laser coherence poses a notable hurdle in achieving high image quality. We propose a new, to the best of our knowledge, architecture of a hybrid dual solid-state light source (HDSSL), which consists of RGB lasers and RGB light-emitting diodes (LEDs). Theoretical analysis and experimental results confirm that the HDSSL can effectively suppress speckle noise. Speckle contrast below 4% on a 70 in. projection image at a distance of 1.5 m has been demonstrated, resulting in a lower speckle contrast than the human speckle perception threshold. Furthermore, the research indicates that increasing the proportion of LEDs in the light source reduces speckle noise.

Structure design and performance optimization of GaAs based betavoltaic microbattery using solid-state tritium source

Structure design and performance optimization of GaAs based betavoltaic microbattery using solid-state tritium source

Differentiating between normal and inflammatory blood serum samples using spectrochemical analytical techniques and chemometrics

Inflammation detection in blood serum samples is commonly performed using clinical analyzers, which are expensive and complex and require specific labels or markers. Spectrochemical analytical techniques, such as laser-induced breakdown spectroscopy (LIBS) and laser-induced fluorescence (LIF), have emerged as alternative methods for qualitative and non-destructive analysis in various fields. This study explores applying LIBS and LIF techniques for label-free discrimination between normal and inflammatory blood serum samples. In the LIBS analysis, the serum samples are deposited on ashless filter paper and exposed to a high-power Nd:YAG laser source to induce plasma emission. The emitted light is dispersed in a spectrometer and an ICCD camera that captures the spectral lines. The LIF technique utilizes a diode-pumped solid-state laser source to excite the blood serum sample placed in a quartz cuvette. The resulting emission spectra are collected and analyzed using a spectrometer equipped with a CCD detector. The obtained spectroscopic data from both techniques is subjected to principal component analysis (PCA) and graph theory for classification and clustering. The PCA classified the two classes with a data variance of 85.4% and 92.8% based on the first two principal components (PCs) for LIBS and LIF spectra. The graph theory clustered the two classes with an accuracy of 76% and 100% based on LIBS and LIF spectra. The statistical methods effectively discriminate between normal and inflammatory serum samples, providing satisfactory results. The proposed spectrochemical methods offer several advantages over traditional clinical analyzers. They are cost-effective and rapid, making them suitable for the fast and reliable identification of serum samples in laboratories. The non-destructive nature of these techniques eliminates the need for specific labels or markers, further streamlining the analysis process.Graphical

Future roles of solid-state quantum dot light sources

This paper highlights the critical role of solid-state quantum dot (QD) light sources in both classical and quantum applications, with an emphasis on their integration with silicon photonics to advance future optical networks and quantum technologies. Quantum dot lasers, renowned for their low threshold currents, temperature stability, low-noise optical amplification, and enhanced coherence, are highlighted as essential components for scalable quantum systems. These features contribute to improved chip architectures, reduced module sizes, and increased channel density. The paper also explores the synergy between quantum dot lasers and silicon photonics in the generation of frequency combs, optimizing efficiency and scalability in optical networks. Furthermore, it delves into the impact of quantum dot-based single-photon sources, particularly their ability to generate entangled and polarized photons, in driving advancements across quantum technologies.

Femtosecond pulses at 914 nm without mode-locking using Nd-doped fiber amplifiers.

We present a fiber laser system that generates femtosecond pulses at 914 nm from a continuous-wave solid-state laser source and using Nd-doped fiber amplifiers. This femtosecond laser architecture without mode-locking is based on picosecond pulse shaping by an electro-optic modulator followed by a Mamyshev regenerator to shorten the pulses down to 8 ps. Additional spectral broadening by self-phase modulation results in an output pulse spectrum of 10 nm, allowing the generation of nearly transform-limited 230 fs pulses.

All solid-state single-frequency DUV source at 248 nm.

An all solid-state single-frequency 248 nm pulsed deep ultraviolet (DUV) source was realized based on multi-stage nonlinear frequency conversions of a 1064 nm fundamental driver. In detail, a 355 nm source, which is the third harmonic wave of 1064 nm laser, and an 827 nm source, which is the signal of an optical parametric oscillator (OPO) pumped by 532 nm laser, are combined for sum-frequency generation (SFG) to get the target wavelength of 248 nm. Finally, an average power of ∼120 mW was obtained at a 4 kHz repetition rate with a pulse width of 4.8 ns. The beam quality factor M2 was measured to be less than 1.5, and the linewidth was estimated to be ∼250 MHz. This method is compact, robust, and requires only one single and easily accessible 1064 nm fundamental driver. The presented 248 nm source could serve as an excellent seed for the KrF excimer laser amplifier to improve the beam quality and coherence.

400 MHz/263 GHz ultra-low temperature MAS-DNP using a closed-cycle helium gas cooling system and a solid-state microwave source.

400 MHz/263 GHz ultra-low temperature MAS-DNP using a closed-cycle helium gas cooling system and a solid-state microwave source.

Multicolor Emission in Indium-Doped Amorphous Boron Nitride Integrated on Silicon for Self-Biased and High-Speed Photodetection.

Boron nitride (BN), as an emergent wide-bandgap material, is gaining considerable attention as a solid-state deep ultraviolet source and quantum emitter from the ultraviolet to the near-infrared spectral ranges. However, studies of the defect structure of BN and efforts at scalable BN emitters in photonic devices are limited. Controlling the BN doping is of particular interest in view of the light emission of defects. Here, it is demonstrated for the first time that doping amorphous BN (a-BN) with indium (In) shows luminescence spectra tuning from blue to red light, and only 765 nm (1.63 eV) light is dominant when more In content is introduced. The visible light emission is found to be the transition between the defect center of InN (a substitutional In of nitrogen) and ONVB (a substitutional oxygen with an adjacent boron vacancy). While ONVB is identified experimentally in accordance with previous theoretical assumptions, and is optically accessible with a zero-phonon line (ZPL) of about 1.63 eV with increasing In proportion. Moreover, the heterogeneous integration of synthesized In-doped a-BN in silicon platforms is demonstrated by the realization of a 700-1000 nm broadband photodetector. These devices operate self-biased at room temperature and show a high photoresponsivity of ∼1.5 A/W (at 980 nm with -2 V bias), a quick response time of ∼90 μs, and a detectivity of 1.02 × 109 cm·Hz1/2/W. This work fundamentally contributes to establishing infrared detection by doping a-BN materials in heterojunctions with Si, at the forefront of infrared optoelectronics.

A new sinter-forging process based on a 915 MHz solid-state microwave source for sintering of oxides ceramics

A new sinter-forging process based on a 915 MHz solid-state microwave source for sintering of oxides ceramics

Broadband stimulated Raman hyperspectral imaging of cells and semiconductors with synchronized fiber and solid-state sources

We demonstrate broadband hyperspectral stimulated Raman scattering (SRS) microscopy covering over 2000 cm−1, which is achieved by two tunable Stokes light sources synchronized with a pump light source. Specifically, a fiber optical parametric oscillator and a fiber laser, both equipped with automatic wavelength tuning capabilities, are employed to acquire SRS signals in the ranges of 270–2040 cm−1 and 2800–3100 cm−1, respectively. Using this system, we perform hyperspectral SRS imaging of live HeLa cells, covering the entire fingerprint and C–H stretching regions. Furthermore, the spectral coverage in the lower fingerprint region (<1000 cm−1) enables SRS signal acquisition of wide bandgap semiconductors. We succeed in obtaining the SRS spectra of 4H-silicon carbide (SiC) and gallium nitride and demonstrate SRS imaging of the longitudinal optical phonon-plasmon coupled mode of 4H-SiC. We anticipate that the present method will further expand the applications of SRS in various scientific fields.

Bound-States-in-the-Continuum-Induced Directional Photoluminescence with Polarization Singularity in WS2 Monolayers.

Monolayer transition metal dichalcogenides are promising materials that not only are atomically thin but also have direct bandgaps, making them highly regarded in optics and optoelectronics. However, their photoluminescence exhibits almost random polarization at room temperature. The emission is also omnidirectional and weak due to the low quantum yield. These limitations hamper the development of practical optoelectronic devices and solid-state single-photon sources for quantum technologies. Here, we demonstrate the spatial control of photoluminescence polarization by coupling monolayer tungsten disulfide with photonic bands having bound states in the continuum. We design a dielectric photonic crystal slab with bound states in the continuum that spectrally overlap with the excitonic resonance of the monolayer of tungsten disulfide. Integration with the photonic crystal slab modulates the directionality and improves the intensity of photoluminescence through extraction and excitation enhancement. Our results will enable the development of compact on-chip optoelectronic and quantum photonic devices based on two-dimensional materials.

A fiber-pigtailed quantum dot device generating indistinguishable photons at GHz clock-rates

Abstract Solid-state quantum light sources based on semiconductor quantum dots (QDs) are increasingly employed in photonic quantum information applications. Especially when moving towards real-world scenarios outside shielded lab environments, the efficient and robust coupling of nanophotonic devices to single-mode optical fibers offers substantial advantage by enabling “plug-and-play” operation. In this work we present a fiber-pigtailed cavity-enhanced source of flying qubits emitting single indistinguishable photons at clock-rates exceeding 1 GHz. This is achieved by employing a fully deterministic technique for fiber-pigtailing optimized QD-devices based on hybrid circular Bragg grating (hCBG) micro-cavities. The fabricated fiber-pigtailed hCBGs feature emission lifetimes of < 80 ${< } 80$ ps, corresponding to a Purcell factor of ∼9, a suppression of multi-photon emission events with g (2)(0) < 1 %, a photon-indistinguishability > 80 ${ >} 80$ % and a measured single-photon coupling efficiency of 53 % in a high numerical aperture single-mode fiber, corresponding to 1.2 Megaclicks per second at the single-photon detectors under 80 MHz excitation clock-rates. Furthermore, we show that high multi-photon suppression and indistinguishability prevail for excitation clock-rates exceeding 1 GHz. Our results show that Purcell-enhanced fiber-pigtailed quantum light sources based on hCBG cavities are a prime candidate for applications of quantum information science.

Terahertz Science and Technology in Astronomy, Telecommunications, and Biophysics.

This paper reviews recent developments and key advances in terahertz (THz) science, technology, and applications, focusing on 3 core areas: astronomy, telecommunications, and biophysics. In THz astronomy, it highlights major discoveries and ongoing projects, emphasizing the role of advanced superconducting technologies, including superconductor-insulator-superconductor (SIS) mixers, hot electron boundedness spectroscopy (HEB), transition-edge sensors (TESs), and kinetic inductance detectors (KIDs), while exploring prospects in the field. For THz telecommunication, it discusses progress in solid-state sources, new communication technologies operating within the THz band, and diverse modulation methods that enhance transmission capabilities. In THz biophysics, the focus shifts to the physical modulation of THz waves and their impact across biological systems, from whole organisms to cellular and molecular levels, emphasizing nonthermal effects and fundamental mechanisms. This review concludes with an analysis of the challenges and perspectives shaping the future of THz technology.

Калибровка внутренних эталонов шумового сигнала радиометра по внешним источникам Igor A.

The possibility of using solid-state noise signal sources as internal standards in a two-stop modulation radiometer is discussed. The dependence of the accuracy of radiometric measurements on the temperatures of internal noise standards is estimated. The possibility of calibrating internal solid-state noise sources against external reference objects with known noise temperatures is being investigated. Formulas for calculating the noise temperatures of internal standards based on known temperatures of external standards are given. The prospect of using a new method of calibration of internal standards to improve the accuracy and stability of radiometric sensing of soils for remote determination of moisture content and soil surface temperature as an element of a precision farming system is analyzed.

A coaxial solid state nonlinear pulse forming line with an exponentially tapered ferrite composite core.

The need to optimize size, weight, and power of high-power microwave (HPM) systems has motivated the development of solid-state HPM sources, such as nonlinear transmission lines (NLTLs), which utilize gyromagnetic precession or dispersion to generate RF. One recent development implemented the NLTL as a pulse forming line (PFL) to form a nonlinear pulse forming line (NPFL) system that substantially reduced the system's size by eliminating the need for a separate PFL; however, matching standard loads can be challenging. This paper describes the development of a tapered NPFL using an exponentially tapered composite based ferrite core containing 60% nickel zinc ferrite (by volume) encased in polydimethylsiloxane (PDMS) and encapsulated in a 5% barium strontium titanate shell. The tapers exponentially change the line's impedance from a 50Ω standard HN connection to 25Ω before tapering back to 50Ω. We characterized the core behavior by obtaining magnetization curves and ferromagnetic resonance measurements. The rise time (10%-90%) of the pulse decreased from ∼6ns for 5kV charging voltage to 1.8ns for 15kV charging voltage. Under unbiased conditions, the system generated HPM with a center frequency of ∼850MHz with a 3 dB bandwidth of 125MHz. Magnetic biases of 15 and 25 kA/m increased the modulation depth and decreased the center frequency to ∼500MHz for 15kV charging voltage.

Design and Experiment of Electromagnetic Pulse Protection Circuit for RF Front End

Abstract This paper introduces the structure and working principle of electromagnetic pulse protection circuit in VHF frequency band in detail. Based on this, a protection circuit with multilevel filtering and transient suppression function is designed. The filter function of the device is realized through a five-order coaxial filter, while the transient suppression feature is accomplished using TVS devices. In order to guarantee the power capacity, the input and output ports of the circuit use N-type connector. Due to good design, the operating bandwidth of the protection circuit exceeds 1.3GHz and the insertion loss is less than 0.5dB. The protective performance of this device was tested by sub-nanosecond solid-state pulse source. The experimental results show that the peak power of electromagnetic protection circuit is greater than 700kW, the suppression capacity is more than 33dB, and the response time is better than 1.4ns.

История развития лазерных технологий в коррекции аметропий: от идей к технологиям

he history of the development of laser technologies goes back about 100 years. It took researchers more than half a century to practically use laser systems in medicine. Despite the well-known fact about the creation of the first laser based on a solid-state radiation source – Meiman ruby, today, in order to perform sublamellar keratomileusis, the vast majority of refractive surgeons use gas excimer lasers to reshape the cornea. Modern installations of this type are high-tech devices, but have a number of disadvantages. In this regard, the search and improvement of alternative sources of UV radiation generation continues in parallel, these include solid-state laser systems. To track trends in the technological development of laser keratorefractive surgery, an analysis of the literature devoted to the history of the stages of development of modern ablative laser systems was carried out. A search and technical comparison of solid-state laser systems available for use in clinical practice was also carried out, identifying their advantages and disadvantages compared to excimer laser systems. Key words: keratorefractive surgery, solid-state laser, excimer laser, history of development, laser vision correction, ablation, UV radiation

Preparation of Multi-Layer Graphene Using Nitrogen-Doped Ultrananocrystalline Diamond as a Solid-State Carbon Source

Preparation of Multi-Layer Graphene Using Nitrogen-Doped Ultrananocrystalline Diamond as a Solid-State Carbon Source