Direct Light Research Articles

Continuous-variable quantum key distribution robust against environmental disturbances.

Continuous variable quantum key distribution (CV-QKD) can guarantee that two parties share secure keys even in the presence of an eavesdropper. However, the polarization direction of the coherent state transmitted in CV-QKD is susceptible to environmental disturbances during channel transmission, making it difficult to share keys consistently over long periods of time. Therefore, a CV-QKD system that can resist environmental disturbance is very urgent. In this paper, we propose a new optical architecture for CV-QKD based on the Faraday-Michelson interference (FMI) structure, and finally form an all-single-mode (SM) fiber-based stable CV-QKD system which employs transmitted local oscillator (TLO) scheme and discrete modulation coherent state (DMCS) protocol. Specifically, since the Faraday mirror rotates the polarization direction of light by 90o, the birefringence effect of light can be effectively dealt with, thus ensuring the same polarization state of light before and after reflection. The final simulation results show that the theoretical secret key rate of this scheme can reach 139 kbps at 70 km, which can further improve the stability and robustness of CV-QKD in the real environment, and provide technical support for the next-generation high-stability QKD system.

Light Activation and Photophysics of a Structurally Constrained Nickel(II)-Bipyridine Aryl Halide Complex.

Transition-metal photoredox catalysis has transformed organic synthesis by harnessing light to construct complex molecules. Nickel(II)-bipyridine (bpy) aryl halide complexes are a significant class of cross-coupling catalysts that can be activated via direct light excitation. This study investigates the effects of molecular structure on the photophysics of these catalysts by considering an underexplored, structurally constrained Ni(II)-bpy aryl halide complex in which the aryl and bpy ligands are covalently tethered alongside traditional unconstrained complexes. Intriguingly, the tethered complex is photochemically stable but features a reversible Ni(II)-C(aryl) ⇄ [Ni(I)···C(aryl)•] equilibrium upon direct photoexcitation. When an electrophile is introduced during photoirradiation, we demonstrate a preference for photodissociation over recombination, rendering the parent Ni(II) complex a stable source of a reactive Ni(I) intermediate. Here, we characterize the reversible photochemical behavior of the tethered complex by kinetic analyses, quantum chemical calculations, and ultrafast transient absorption spectroscopy. Comparison to the previously characterized Ni(II)-bpy aryl halide complex indicates that the structural constraints considered here dramatically influence the excited state relaxation pathway and provide insight into the characteristics of excited-state Ni(II)-C bond homolysis and aryl radical reassociation dynamics. This study enriches the understanding of molecular structure effects in photoredox catalysis and offers new possibilities for designing customized photoactive catalysts for precise organic synthesis.

CASE REPORT : OLFACTORY GROOVE MENINGIOMA

Abstract
 Background: Olfactory Groove Meningiomas (OGM) are a rare cause of olfactory dysfunction. OGMs are benign, slow-growing tumors that cause non-specific symptoms, such as headaches, olfactory impairment, and psychiatric symptoms, such as depression, personality changes, decreased cognitive function, visual problems, or seizures.
 Aim: In this case report we would like to discuss about a rare case of olfactory groove meningioma with non-spesific symptoms presented in 47-year old female patient
 Case report: A 47-year old female with progressive blurred vision in the right eye for 3 months. Negative light perception in the right eye and fundus of the right eye indicated papillary atrophy. The direct and indirect light reflexes were negative in the right eye. We found Strong homogenous contrast enhancement extraaxial lesion accompanied by multiple dural tails in the left frontal convexity UK approximately 3.2 x 2.8 x 3.1 cm, Tuberculum sellae approximately 2.7 x 2.9 x 3 cm. Cranial decompression, frontal bone reconstruction, and tumor removal were performed. It was found that there was microcystic growth of tumor tissue, consisting of proliferation of meningoethelial cells, round to oval nuclei, smooth chromatin, visible intranuclear inclusions
 Discussion: OGM is a rare, benign tumor. Female patients were more likely to develop OGM than male patients. The ciliary ganglion of cranial nerve III may be affected by compression of the tumor, resulting in the absence of direct and indirect pupillary reflexes in the affected eyes.
 Conclusion: OGM is a slow-growing tumor that does not show significant symptoms at an early stage, making early detection difficult.
 Keyword: Olfactory Groove Meningioma, Blurred Vision, Meningioma

Orientational effects in the polarized absorption spectra of molecular aggregates.

We present a detailed theoretical analysis of polarized absorption spectra and linear dichroism of cyanine dye aggregates whose unit cells contain two molecules. The studied threadlike ordered system with a molecular exciton delocalized along its axis can be treated as two chains of conventional molecular aggregates, rotated relative to each other at a certain angle around the aggregate axis. Our approach is based on the general formulas for the effective cross section of light absorption by a molecular aggregate and key points of the molecular exciton theory. We have developed a self-consistent theory for describing the orientational effects in the absorption and dichroic spectra of such supramolecular structures with nonplanar unit cell. It is shown that the spectral behavior of such systems exhibits considerable distinctions from that of conventional cyanine dye aggregates. They consist in the strong dependence of the relative intensities of the J- and H-type spectral bands of the aggregate with a nonplanar unit cell on the angles determining the mutual orientations of the transition dipole moments of constituting molecules and the aggregate axis as well as on the polarization direction of incident light. The derived formulas are reduced to the well-known analytical expressions in the particular case of aggregates with one molecule in the unit cell. The calculations performed within the framework of our excitonic theory combined with available vibronic theory allow us to quite reasonably explain the experimental data for the pseudoisocyanine bromide dye aggregate.

Dual-polarization defogging method based on frequency division and blind separation of polarization information.

The current advancements in image processing have led to significant progress in polarization defogging methods. However, most existing approaches are not suitable for scenes with targets exhibiting a high degree of polarization (DOP), as they rely on the assumption that the detected polarization information solely originates from the airlight. In this paper, a dual-polarization defogging method connecting frequency division and blind separation of polarization information is proposed. To extract the polarization component of direct transmission light from the detected polarized signal, blind separation of overlapped polarized information is performed in the low-frequency domain based on visual perception. Subsequently, after estimating airlight, a high-quality defogging image can be restored. Extensive experiments conducted on real-world scenes and comparative tests confirm the superior performance of our proposed method compared to other competitive methods, particularly in reconstructing objects with high DOP. This work provides a quantitative approach for estimating the contributions of polarization light from different sources and further expands the application range of polarimetric defogging imaging.

Infrared plasmonic refractive index sensor utilizing 2D grating of nano-bowtie particles for both gas and liquid

We propose a plasmonic structure that can be used for refractive index sensing with different analytes in the same wavelength-domain. A two-dimensional (2D) grating composed of nano-bowtie particles is used as the optical momentum coupling structure. The double-period feature of the 2D grating makes the structure have two excitation approaches with different polarization directions of incident light. The physical mechanisms of the plasmonic structure are revealed in detail by theoretical analysis and finite-difference time-domain method. The simulation results show that the structure can achieve a gas sensing sensitivity of 1235 nm/RIU and a liquid sensing sensitivity of 950 nm/RIU in the same wavelength-domain from 1200 nm to 1400 nm. This structure can be widely used in the field of gas or liquid biochemistry due to its simple geometry and competitive sensing performance.

Bilateral Ocular Ischaemic Syndrome due to Carotid Artery and Cardiovascular Disease: A Case Report

Introduction : Ocular ischemic syndrome (OIS) is a rare but potentially blinding and fatal condition caused by carotid artery disease or other systemic condition results in ocular hypoperfusion.
 Case Illustration : A 62-year-old male with sudden bilateral vision loss, swelling, redness and pain of both eye for 7 days. There were dilated conjunctival and episcleral vessels, visual acuity of the right eye was hand movement and 0.05 for left eye, intraocular pressure (IOP) was 33 mmHg in right eye and 37 mmHgfor left eye. Anterior segment evaluation revealed rubeosis iris, mild anterior chamber reaction, and temporal angle neovascularization on gonioscopy. Both direct and consensual light reflexes were sluggish. Fundus examination showed normal optic disc, minimal hemorrhages at mid-periphery, narrowed arterioles, and minimal cotton wool spot. Macular OCT demonstrated discrete hyperreflectivity of inner retinal layers. From Macular Angiography OCT, ETDRS Central vessel density were 11.2% and 17.6% for the right eye and left eye, respectively. In both eyes, paracentesisof anterior chamber, intravitreal and intracameral injections of anti-VEGF were performed. Brain Magnetic Resonance Angiography Imaging revealed moderate stenosis of both distal carotid artery circulation. Percutaneous Coronary Angiography showed extensive stenosis in coronary artery, with low Ejection Fraction.
 Discussion : For the cardiovascular management, a pacemaker was implanted. One week after procedure, BCVA were 1/60 and 0.15, and IOPs of 17 and 18 mmHg, for the right and left eye, respectively. The patient was scheduled to have laser retinal photocoagulation.
 Conclusion : Quick clinical diagnosis, targeted workup for systemic associations, and prompt treatment might preserve life and sight in OIS.

Intelligent Evacuation Sign Control Mechanism in IoT-Enabled Multi-Floor Multi-Exit Buildings.

In contemporary evacuation systems, the evacuation sign typically points fixedly towards the nearest emergency exit, providing guidance to evacuees. However, this static approach may not effectively respond to the dynamic nature of a rapidly evolving fire situation, in particular if the closest emergency exit is compromised by fire. This paper introduces an intelligent evacuation sign control mechanism that leverages smoke and temperature sensors to dynamically adjust the direction of evacuation signs, ensuring evacuees are guided to the quickest and safest emergency exit. The proposed mechanism is outlined through a rigorous mathematical formulation, and an ESP heuristic is devised to determine temperature-safe, smoke-safe, and congestion-aware evacuation paths for each sign. This algorithm then adjusts the direction light on the evacuation sign to align with the identified evacuation path. To validate the effectiveness of this approach, fire simulations using FDS software 6.7.1 were conducted in the Taipei 101 shopping mall. Temperature and smoke data from sensor nodes were utilized by the ESP algorithm, demonstrating superior performance compared to that of the existing FEL algorithm. Specifically, the ESP algorithm exhibited a notable increase in the probability of evacuation success, surpassing the FEL algorithm by up to 34% in methane fire scenarios and 14% in PVC fire scenarios. The significance of this improvement is more pronounced in densely congested evacuation scenarios.

The Development of a Modular Adaptive Facade System Based on Pre - Calculated Light Values Through Parametric Models and Real - Time Light Sensors

The design of exhibitions often faces limitations in utilizing natural light inside the building due to the diverse and rotating nature of exhibited artworks. These objects have varying light sensitivity and prolonged exposure to excessive light can cause damage or deterioration. Therefore, in exhibition design, it is crucial to consider the direction and quantity of light that falls on the displayed objects to protect them from potential harm caused by natural light and extend their longevity. Consequently, the factor of utilizing natural light within exhibition spaces becomes a challenging element to control. The goal of this research is to develop an adaptable building envelope system to control the amount of natural light in response to the use of exhibition spaces. This was achieved by creating a parametric model using Rhinoceros software and its Grasshopper plugin for designing the building envelope. Together with the use of physical computing to create a hardware system that was programmed to develop a prototype of an adaptable building envelope we have developed a process able to optimize lighting delivery for exhibited objects. The building envelope has adjustable openings that correspond to the position of the exhibited objects and the sun. The building envelope can serve as a sunshade to prevent direct sunlight from impacting the exhibited objects while allowing the utilization of natural light in other areas within the exhibition space. The results of this research demonstrate suitable building facade designs that can be applied to exhibition spaces in various projects. The researchers evaluated the performance of the model by simulating exhibition spaces equipped with the building facade system in the southern and western directions and measured the intensity of light entering the exhibition areas. Results showed an average light intensity for the spaces ranging from 30 to 90 lux, which does not cause any damage to the exhibited objects. The researchers also tested the functionality of the building facade system with natural light and found that the control system and mechanisms worked accurately, reducing the sunlight intensity by 97.3%. This adaptable building facade system can address complex architectural design challenges and allow architects to control the amount of natural light within exhibition spaces. The design flexibility of the facade envelope system allows it to respond to different daylight periods that vary seasonally and would impact the exhibited objects.

Integrating Smart Greenhouse Cover, Reduced Nitrogen Dose and Biostimulant Application as a Strategy for Sustainable Cultivation of Cherry Tomato

Fruit yield and quality of greenhouse tomatoes are strongly influenced by light conditions and nitrogen (N) availability, however, the interaction between these factors is still unclear. We evaluated the effects on cherry tomatoes of two tunnel plastic covers with different optical properties and three N doses, also in combination with a biostimulant treatment. We compared a diffuse light film (Film1) and a conventional clear film (Film2), and three N levels, corresponding to 50% (N50), 75% (N75) and 100% (N100) of the optimal dose, with and without a microbial plus a protein hydrolysed biostimulant, compared to a non-treated control. The three experimental treatments significantly interacted on several yield and quality parameters. In control plants (untreated with biostimulants), the early yield was higher at reduced N doses compared to N100, with greater increments under the diffusive Film1 compared to the clear Film2 (+57.7% and +37.0% vs. +31.7% and +16.0%, in N50 and N75 respectively). Film1 boosted the total fruit production at all the N rates and with or without biostimulants, compared to Film2, with stronger effects under sub-optimal N (+29.4% in N50, +21.2% in N75, and +7.8% in N100, in plants untreated with biostimulant). Total yield decreased with decreasing N levels, while it always increased with the application of biostimulants, which counterbalanced the detrimental effects of N shortage. Quality traits were mainly affected by the cover film and the biostimulant treatment. The diffusive film increased the content of carotenoids, lycopene and total phenols compared to the clear one, and the biostimulants increased texture, soluble solids, phenols and ascorbic acid compared to the untreated control. It is worth noting that in plants fertilized at 75% of the reference N dose, the biostimulants determined higher yield than the N100 untreated control, under both the covers (+48% in Film1 and +20% in Film2). In conclusion, the diffusive film improved the fruit yield and quality of greenhouse tomatoes in the spring–summer period, presumably avoiding plant stress due to high-intensity direct light. Reduced N rates limited the plant productivity, however, the biostimulant application was effective in compensating for the detrimental effects of sub-optimal supply of N synthetic fertilizers.

Improved Adhesion of Direct Copper Seed Layer by Medium-Vacuum Sputtering Using Vacuum Ultraviolet Light

A sputtering method is used to form the seed layer for copper electric plating. In general, copper sputtering has weak adhesion to resin, so titanium sputter is combined to increase the adhesion strength. However, etching in the lithography process requires two types of processes, titanium and copper metal. Adhesion strength was improved by performing vacuum ultraviolet (VUV) treatment as a pretreatment for medium-vacuum sputtering. We discovered the relationship between the hydroxyl groups on the resin surface and the adhesion strength by the chemical modification XPS method. Furthermore, by XPS analysis of the peeled copper interface, the adhesion mechanism between the resin and copper due to VUV irradiation was estimated. We evaluated the absorption properties in the vacuum ultraviolet region of a thinly polished glass epoxy resin. We investigated the behavior of functional groups at the interface and considered the effect of vacuum ultraviolet light in the depth direction.

Direct white light luminescence from Ho3+/Pr3+ co-doped fluoride fiber with blue diode pumping

White light luminescence induced by a blue diode laser was investigated in a double-clad Ho3+/Pr3+ co-doped ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fiber. The pump laser at 442 nm can simultaneously excite Ho3+ and Pr3+ ions, resulting in synergistic luminescence. The emission spectra include multiple visible bands in the blue, green, orange, red, and deep-red spectral regions, which correspond to the 4f-4f electronic transitions of Ho3+ and Pr3+ ions. The relative intensity of emission bands is dependent on the pump power, and the CIE 1931 chromaticity diagram illustrates the dependence of color tunability on the pump power. Under laser excitation at 442 nm, the CIE coordinates are within the white light range, and the CCT values are between 6900 and 8700 K. The results indicate that double-clad Ho3+/Pr3+ co-doped ZBLAN fibers that are directly blue diode-pumped have the potential to be used in high-power white light fiber lasers.

Camphoric Acid in Nanomagnetic Photocatalyst Synthesis: Direct and Indirect Visible Light Photocatalytic Degradation of PCBs

Camphoric Acid in Nanomagnetic Photocatalyst Synthesis: Direct and Indirect Visible Light Photocatalytic Degradation of PCBs

Evaluation on Surface Characteristics, Accuracy, and Dimensional Stability of Tooth Preparation Dies Fabricated by Conventional Gypsum and 3D-Printed Workflows.

To evaluate the surface characteristics, accuracy (trueness and precision), and dimensional stability of tooth preparation dies fabricated using conventional gypsum and direct light processing (DLP), stereolithography (SLA), and polymer jetting printing (PJP) techniques. Gypsum preparation dies were replicated according to the reference data and imported into DLP, SLA, and PJP printers, and the test data were obtained by scanning after 0, 1, 3, 7, 14, 28, and 42 days. After analyzing the surface characteristics, a best-fit algorithm between the test and the reference data was used to evaluate the accuracy and dimensional stability of the preparation dies. The data were analyzed by one-way analysis of variance and Tukey test or Kruskal-Wallis H test (α = .05). Compared with the gypsum group (3.61 ± 0.59 μm), the root mean square error (RMSE) values of the SLA group (5.33 ± 0.48 μm) was rougher (P < .05), the PJP group (2.43 ± 0.37 μm) was smoother (P < .05), and the DLP group (2.92 ± 0.91 μm) had no significant difference (P > .05). For trueness, the RMSE was greater in the PJP (34.90 ± 4.91 μm) and SLA (19.01 ± 0.95 μm) groups than in the gypsum (16.47 ± 0.47 μm) group (P < .05), and no significant difference was found between the DLP (17.10 Å} 1.77 μm) and gypsum groups. Regarding precision, the RMSE ranking was gypsum = DLP = SLA < PJP group. The RMSE ranges in the gypsum, DLP, PJP, and SLA groups at different times were 6.79 to 8.86 μm, 5.44 to 10.17 μm, 10.16 to 11.28 μm, and 10.94 to 32.74 μm, respectively. Although gypsum and printed preparation dies showed statistically significant differences in surface characteristics, accuracy, and dimensional stability, all tooth preparation dies were clinically tolerated and used to produce fixed restorations.

Esketamine: Less Drowsiness, More Analgesia.

Racemic ketamine is a 1:1 mixture of 2 enantiomers that turn light in opposite direction: Dextrorotatory esketamine is approximately 4 times more affine for the N-methyl-D-aspartate (NMDA) receptor than levorotatory arketamine, which may explain why esketamine is about twice as potent as an analgesic and anesthetic as the racemate. Esketamine has attracted renewed interest in view of the opioid crisis, racemic ketamine's abuse, and esketamine's approval for expanded use. We evaluated the anesthesia literature concerning mental, cardiovascular, cerebral, and antinociceptive effects of esketamine published in English between 1980 and 2022. The review shows that esketamine and racemic ketamine are not "the same" at clinically equivalent analgesic and anesthetic dose: Psychomimetic effects seem to be essentially related to NMDA receptor blockade and esketamine is not devoid of unwanted mental impact. However, it probably involves less cholinergic inhibition. Cognitive disturbances during arousal, awakening, and recovery from the drug are less, and less pronounced with esketamine. The drug allows for an approximately 50% dose reduction in anesthesia and analgesia which goes along with a higher clearance and shorter recovery time as compared to racemic ketamine. In comparison of esketamine with placebo, esketamine shows cardiocirculatory stabilizing and neuroprotective effects which can be seen in anesthesia induction, cardiac surgery, and analgesia and sedation in brain injury. Evidence of esketamine's antinociceptive efficacy is inconsistent, although a recent meta-analysis reports improved pain relief after surgery in a study with short observation time. To better define esketamine's place, direct head-to-head comparison with the racemate at equi-analgesic/anesthetic dose is warranted.

Photophobotaxis in the filamentous cyanobacterium Phormidium lacuna: Mechanisms and implications for photosynthesis-based light direction sensing.

Cyanobacterium Phormidium lacuna filaments move from dark to illuminated areas by twitching motility. Time-lapse recordings demonstrated that this photophobotaxis response was based on random movements with movement reversion at the light-dark border. The filaments in the illuminated area form a biofilm attached to the surface. The wild-type and the pixJ and cphA mutants were investigated for photophobotaxis at diverse wavelengths and intensities. CphA is a cyanobacterial phytochrome; PixJ is a biliprotein with a methyl-accepting chemotaxis domain and is regarded as a phototaxis photoreceptor in other species. The cphA mutant exhibited reduced biofilm surface binding. The pixJ mutant was characterized as a negative photophobotaxis regulator and not as a light direction sensor. 3-(3,4-dichlorophenyl)1,1-dimethylurea (DCMU) blocks electron transfer in PS II. At concentrations of 100 and 1000 μM DCMU, photophobotaxis was inhibited to a greater extent than motility, suggesting that PSII has a role in photophobotaxis. We argue that the intracellular concentrations of regular photoreceptors, including CphA or PixJ, are too small for a filament to sense rapid light intensity changes in very weak light. Three arguments, specific inhibition by DCMU, broad spectral sensitivity, and sensitivity against weak light, support photosynthesis pigments for use as photophobotaxis sensors.

Emergence of threefold symmetric helical photocurrents in epitaxial low twinned Bi2Se3

We present evidence of a strong circular photon drag effect (PDE) in topological insulators (TIs) through the observation of helicity-dependent topological photocurrents with threefold rotational symmetry using THz spectroscopy in epitaxially-grown Bi2Se3 with reduced crystallographic twinning. We establish how twinned domains introduce competing nonlinear optical (NLO) responses inherent to the crystal structure that obscure geometry-sensitive optical processes through the introduction of a spurious mirror symmetry. Minimizing the twinning defect reveals strong NLO response currents whose magnitude and direction depend on the alignment of the excitation to the crystal axes and follow the threefold rotational symmetry of the crystal. Notably, photocurrents arising from helical light reverse direction for left/right circular polarizations and maintain a strong azimuthal dependence-a result uniquely attributable to the circular PDE, where the photon momentum acts as an applied in-plane field stationary in the laboratory frame. Our results demonstrate new levels of control over the magnitude and direction of photocurrents in TIs and that the study of single-domain films is crucial to reveal hidden phenomena that couple topological order and crystal symmetries.

Proximity-Based Optical Camera Communication with Multiple Transmitters Using Deep Learning.

In recent years, optical camera communication (OCC) has garnered attention as a research focus. OCC uses optical light to transmit data by scattering the light in various directions. Although this can be advantageous with multiple transmitter scenarios, there are situations in which only a single transmitter is permitted to communicate. Therefore, this method is proposed to fulfill the latter requirement using 2D object size to calculate the proximity of the objects through an AI object detection model. This approach enables prioritization among transmitters based on the transmitter proximity to the receiver for communication, facilitating alternating communication with multiple transmitters. The image processing employed when receiving the signals from transmitters enables communication to be performed without the need to modify the camera parameters. During the implementation, the distance between the transmitter and receiver varied between 1.0 and 5.0 m, and the system demonstrated a maximum data rate of 3.945 kbps with a minimum BER of 4.2×10-3. Additionally, the system achieved high accuracy from the refined YOLOv8 detection algorithm, reaching 0.98 mAP at a 0.50 IoU.

A precise compensation algorithm for visual measurement in non-uniform refractive index environment based on Hamiltonian ray tracing method

In complex large-scale industrial environments, light rays no longer propagate in a straight line due to the influence of non-uniform refractive index, which will lead to large measurement errors in visual measurement. In order to accurately compensate the error, this paper firstly quantitatively analyzes the influence of non-uniform refractive index distribution on visual measurement. Then the symplectic matrix ray-tracing method of Hamiltonian optics is used to reconstruct spatial light in the reverse direction with known light propagation end point and spatial refractive index distribution. Thus the traditional model of light propagation along a straight line in visual measurement can be changed and the measurement error introduced by non-uniform refractive index field can be corrected. Finally, the proposed Hamiltonian ray tracing method was verified through the spatial non-uniform refractive index field reconstructed by Background Oriented Schlieren(BOS) method. The experimental results verified the effectiveness and feasibility of this method.

Rhodanine-Based Chromophores: Fast Access to Capable Photoswitches and Application in Light-Induced Apoptosis.

Molecular photoswitches are highly desirable in all chemistry-related areas of research. They provide effective outside control over geometric and electronic changes at the nanoscale using an easy to apply, waste-free stimulus. However, simple and effective access to such molecular tools is typically not granted, and elaborate syntheses and substitution schemes are needed in order to obtain efficient photoswitching properties. Here we present a series of rhodanine-based photoswitches that can be prepared in one simple synthetic step without requiring elaborate purification. Photoswitching is induced by UV and visible light in both switching directions, and thermal stabilities of the metastable states as well as quantum yields are very high. An additional benefit is the hydrogen-bonding capacity of the rhodanine fragment, which enables applications in supramolecular or medicinal chemistry. We further show that the known rhodanine-based inhibitor SMI-16a is a photoswitchable apoptosis inducer. The biological activity of SMI-16a can effectively be switched ON or OFF by reversible photoisomerization between the inactive E and the active Z isomer. Rhodanine-based photoswitches therefore represent an easy to access and highly valuable molecular toolbox for implementing light responsiveness to the breadth of functional molecular systems.