Photon Drag Research Articles

Observation of Hot Carrier Localization Affected by A Cations in Hybrid Perovskites.

Organic-inorganic lead halide perovskites (OLHPs) have demonstrated exceptional properties in high-performance photoelectric devices. However, the impact of A-site cations, specifically formamidinium and methylammonium (MA), on the optoelectronic properties of OLHPs, particularly in the context of hot carrier utilization, remains a topic of debate. In this study, we propose a method for characterizing hot carrier transportation by measuring the hot carrier mobility and momentum-dependent transient photocurrent influenced by A-site cations in OLHPs. Our findings reveal that the direction of photon drag current is reversed upon substitution of the MA cation, suggesting the strong localization of hot carriers by the MA cation dipole. Furthermore, the correlation between the hot carrier photoconductivity and the electronic structure in different A-site cation samples indicates that hot carrier mobility in OLHPs can be reduced by >50% due to the influence of A-site cations.

Germanium Single Crystals for Photonics

Germanium (Ge) is a system-forming material of IR photonics for the atmospheric transparency window of 8–14 µm. For optics of the 3–5 µm range, more widespread silicon (Si), which has phonon absorption bands in the long-wave region, is predominantly used. A technology for growing Ge single crystals has been developed, allowing the production of precision optical parts up to 500 mm in diameter. Ge is used primarily for the production of transparent optical parts for thermal imaging devices in the 8–14 µm range. In addition, germanium components are widely used in a large number of optical devices where such properties as mechanical strength, good thermal properties, and climatic resistance are required. A very important area of application of germanium is nonlinear optics, primarily acousto-optics. The influence of doping impurities and temperature on the absorption of IR radiation in germanium is considered in detail. The properties of germanium photodetectors are reported, primarily on the effect of photon drag of holes. Optical properties in the THz range are considered. The features of optical properties for all five stable isotopes of germanium are studied. The isotopic shift of absorption bands in the IR region, caused by phonon phenomena, which was discovered by the authors for the first time, is considered.

Amplification of rotary photon drag using Laguerre-Gaussian beam of control field

Amplification of rotary photon drag using Laguerre-Gaussian beam of control field

Manipulation of Helicity-Dependent Photocurrent and Stokes Parameter Detection in Topological Insulator Bi2Te3 Nanowires.

Helicity-dependent photocurrent (HDPC) and its modulation in topological insulator Bi2Te3 nanowires have been investigated. It is revealed that when the incident plane of a laser is perpendicular to the nanowire, the HDPC is an odd function of the incident angle, which is mainly contributed by the circular photogalvanic effect originating from the surface states of Bi2Te3 nanowire. When the incident plane of a laser is parallel to the nanowire, the HDPC is approximately an even function of the incident angle, which is due to the circular photon drag effect coming from the surface states. It is found that the HDPC can be effectively tuned by the back gate and the ionic liquid top gate. By analyzing the substrate dependence of the HDPC, we find that the HDPC of the Bi2Te3 nanowire on the Si substrate is an order of magnitude larger than that on SiO2, which may be due to the spin injection from the Si substrate to the Bi2Te3 nanowire. In addition, by applying different biases, the Stokes parameters of a polarized light can be extracted by arithmetic operation of the photocurrents measured in the Bi2Te3 nanowire. This work suggests that topological insulator Bi2Te3 nanowires may provide a good platform for opto-spintronic devices, especially in chirality and polarimtry detection.

The impact of cross-Kerr nonlinearity on rotary photon drag and temporal cloaking in Sagnac interferometry

We theoretically explore the impact of cross-Kerr nonlinearity (CKN) on rotary photon drag (RPD) and temporal cloaking in a Sagnac interferometer. With the activation of CKN, significant improvements in RPD and temporal cloaking are observed. Drag angles of ±1×10−3 and ±5×10−3 radians are attained, similarly, temporal gaps of 10μ s, 12μ s and 13μ s are observed. In addition to the observed electromagnetically induced transparency window, the group refractive index is drastically enhanced, time delay/advance are tuned from pico-radians to micro-radians, and reduced relativistic group velocities are achieved by activating CKN within the system. Additionally, the transmission pulses intensities are observed to be reduced with the dragging phenomenon. The findings may have potential applications in controlled image coding, rotation sensing and secure communication technologies.

Emerging Nonlinear Photocurrents in Lead Halide Perovskites for Spintronics.

Lead halide perovskites (LHPs) containing organic parts are emerging optoelectronic materials with a wide range of applications thanks to their high optical absorption, carrier mobility, and easy preparation methods. They possess spin-dependent properties, such as strong spin-orbit coupling (SOC), and are promising for spintronics. The Rashba effect in LHPs can be manipulated by a magnetic field and a polarized light field. Considering the surfaces and interfaces of LHPs, light polarization-dependent optoelectronics of LHPs has attracted attention, especially in terms of spin-dependent photocurrents (SDPs). Currently, there are intense efforts being made in the identification and separation of SDPs and spin-to-charge interconversion in LHP. Here, we provide a comprehensive review of second-order nonlinear photocurrents in LHP in regard to spintronics. First, a detailed background on Rashba SOC and its related effects (including the inverse Rashba-Edelstein effect) is given. Subsequently, nonlinear photo-induced effects leading to SDPs are presented. Then, SDPs due to the photo-induced inverse spin Hall effect and the circular photogalvanic effect, together with photocurrent due to the photon drag effect, are compared. This is followed by the main focus of nonlinear photocurrents in LHPs containing organic parts, starting from fundamentals related to spin-dependent optoelectronics. Finally, we conclude with a brief summary and future prospects.

Investigation of helicity dependent photocurrent of the surface states in a (Bi0.7Sb0.3)2Te3 nanoplate

Abstract Helicity dependent photocurrent (HDPC) of the surface states in a high-quality topological insulator (Bi$_{0.7}$Sb$_{0.3}$)$_2$Te$_3$ nanoplate grown by chemical vapor deposition (CVD) is investigated. By investigating the angle dependent HDPC, it is found that the HDPC is mainly contributed by the circular photogalvanic effect (CPGE) current when the incident plane is perpendicular to the connection of the two contacts, whereas the circular photon drag effect (CPDE) dominates the HDPC when the incident plane is parallel to the connection of the two contacts. In addition, the CPGE of the (Bi$_{0.7}$Sb$_{0.3}$)$_2$Te$_3$ nanoplate is regulated by temperature, light power, excitation wavelength, the source-drain and ionic liquid top-gate voltages, and the regulation mechanisms are discussed. It is demonstrated that (Bi$_{0.7}$Sb$_{0.3}$)$_2$Te$_3$ nanoplates may provide a good platform for novel opto-spintronics devices.

Helicity-dependent photocurrent of topological surface states in the intrinsic magnetic topological insulator MnBi2Te4

Helicity-dependent photocurrent (HDPC) of the topological surface states (TSSs) in the intrinsic magnetic topological insulator MnBi2Te4 is investigated. It is revealed that the HDPC is mainly contributed by the circular photogalvanic effect (CPGE) current when the incident plane is perpendicular to the connection of the two electrodes, while the circular photon drag effect plays the dominant role when the incident plane is parallel to the connection of the two electrodes. The CPGE current shows an odd function dependence on incident angles, which is consistent with the C3v symmetry group of the TSSs in MnBi2Te4. The amplitude of the CPGE current increases with the decrease in temperature, which can be attributed to the increase in mobility at low temperatures, confirmed by the transport measurements. Furthermore, we modulate the CPGE of MnBi2Te4 by applying top gate and source–drain voltages. Compared to Bi2Te3 of the same thickness, the CPGE current of MnBi2Te4 can be more effectively tuned by the top gate because the Fermi level of MnBi2Te4 can be effectively regulated by the top gate, and it is tuned across the Dirac point. This work suggests that the intrinsic magnetic topological insulator MnBi2Te4 is a good candidate for designing opto-spintronics devices.

Ac Hall Effect and Photon Drag of Superconducting Condensates.

We suggest a theoretical description of the photogalvanic phenomena arising in superconducting condensates in the field of electromagnetic wave. The ac Hall effect and photon drag are shown to originate from the second-order nonlinear response of superconducting carriers caused by the suppression of their concentration due to the combined influence of the electron-hole asymmetry and charge imbalance generated by the incident electromagnetic wave. Starting from the time-dependent Ginzburg-Landau theory with the complex relaxation constant, we develop a phenomenological description of these phenomena and investigate the resulting behavior of the dc supercurrent and second harmonic induced by microwave radiation incident on a superconductor surface.

Giant Photon‐Drag‐Induced Ultrafast Photocurrent in Diamond for Nonlinear Photonics

AbstractDiamond is emerging as an attractive third‐generation wide‐bandgap semiconductor for future on‐chip nonlinear photonics and quantum optics due to its unique thermal, optical, and mechanical properties. However, the light‐driven current under below‐band gap excitation from the second‐order nonlinear optical effect in diamond is still challenging. Herein, a giant second‐order nonlinear photocurrent is observed in the chemical vapor deposition (CVD) diamond by utilizing terahertz (THz) emission spectroscopy. This ultrafast photocurrent originates from the photon drag effect (PDE), during which the momentum transfer from the incident photons to the charge carriers at the rich grain boundaries of the CVD diamond after the exclusive subgap π–π* transition upon femtosecond laser excitation. Especially, the interplay between circular and linear PDE to the THz generation is clarified and distinguished under elliptically polarized light excitation. Furthermore, the picosecond ultrafast dynamics of these charge carriers are also verified by infrared spectroscopy. Owing to the giant photon‐drag‐induced ultrafast photocurrent, the CVD diamond presents the highest THz emission efficiency compared with the reported carbon allotropes, which expands the new functionality of diamond nonlinear photonics into on‐chip THz devices.

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.

Sagnac interferometry and the impact of conductivity-dependent Raman gain on rotary photon drag

We theoretically demonstrate the impact of conductivity-dependent Raman gain (RG) on rotary photon drag (RPD) in a Sagnac interferometer (SI). The presence of conductivity-dependent Raman gain results in enhanced RPD angles, ranging from θ d = ± 0.56 radians to θ d = ± 0.7 radians. The susceptibility, group index, relativistic group velocities, and RPD exhibit significant fluctuations with changes in the conductivity phase. Specifically, we observe gain-singlets when the control field is deactivated, while gain doublets are achieved when the control field is activated. Moreover, within the gain regions, we observe normal dispersion, whereas anomalous dispersion is observed around the gain regions. These findings have potential applications in controlled image coding/design, four-wave mixing, photo detectors, light modulation, and phase-matching in Brillouin scattering.

Sensitivity of atom based on slow light propagation and rotary photon drag: an efficient and secure model for quantum-based sensors in Internet of Things

Quantum technology has the potential to revolutionize sensors and the Internet of Things (IoT). Efficient and secure data transfer among sensors and IoT devices is a major challenge. To address this, the manuscript presents coherent manipulation of the scattering cross section and its sensitivity based on subluminal propagation and rotary photon drag, using an atomic medium with two levels coupled with a cavity. The group index of the proposed atomic medium is measured in the range of -0.1le n_gle 150 and group velocity in the range of 2times 10^6m/sle v_gle pm 2times 10^9m/s. The maximum delay time is reported to t_g=0.3mu s and rotary photon drag to theta _d=pm 5 micro radian. This effect of photon drag is used in sensing, energy harvesting, and optical switching in IoT. The scattering cross-section of 0.1times 10^{21}m^2 is reported. The scattering cross-section impacts the efficiency and reliability of quantum-based communication for IoT. The maximum cross-sectional sensitivity is measured to S_sigma =0.4times 10^{-19}m^2/n_r. The cross-sectional sensitivity potentially impacts secure communication and highly precise detection in sensors and IoT.

Ultrafast helicity-dependent photocurrents in Weyl Magnet Mn3Sn

Mn3Sn is a material that has attracted a lot of attention lately for its topologically non-trivial band structure, which leads to very promising spintronic properties. In this work we experimentally demonstrate that an epitaxially grown thin film of Mn3Sn acts as a source of THz radiation at room temperature when irradiated by a femtosecond laser pulse. By combining various experimental measurements as a function of pump polarisation, magnetic field, and sample orientation we are able to explain the origin of the THz emission with the photocurrents generated via the photon drag effect. A thorough symmetry analysis combined with electronic band structure calculations using density-functional theory (DFT) are used to support our conclusions and provide a guide towards the important features that lead to photocurrent generation, which is useful for designing ultra-fast current pulses emitters.

Gate voltage control of helicity-dependent photocurrent and polarization detection in (Bi1−xSbx)2Te3 topological insulator thin films

Optical helicity provides us with an effective means to control the helicity-dependent photocurrent in the spin-momentum-locked surface states of topological insulators (TIs). Also, the TIs show potential in polarization detection as an intrinsic solid-state optical chirality detector for easier integration and fabrication. However, the complex photoresponses with the circular photogalvanic effect, the linear photogalvanic effect, and the photon drag effect in the TIs prevent them from direct chirality detection of the elliptically polarized light. Here, by fitting with the theoretical models to the measured photocurrents, the microscopic origin of different components of the helicity-dependent photocurrent has been demonstrated. We show a comprehensive study of the helicity-dependent photocurrent in (Bi1−xSb x )2Te3 thin films of different thicknesses as a function of the light incident angle and the gate-tuned chemical potential. The observation of the light incident angle dependence of the helicity-dependent photocurrent provides us with a polarization detection strategy using a TI thin film without the use of any additional optical elements, and the detection accuracy can be enhanced by gate tuning. Additionally, the Stokes parameters can be extracted by arithmetic operation of photocurrents measured with different incident angles and gating voltages for complete characterization of the polarization states of a light beam. Using this means, we realize the polarization detection and the Stokes parameters analysis with a single device. Our work provides an alternative solution to develop miniaturized intrinsic polarization-sensitive photodetectors.

Dispersion-dependent superluminal propagation and photon drag in GaAs/AlGaAs quantum dot molecule

Controlling the basic properties of light such as polarization, angular momentum, and speed through various optical media leads to interesting phenomena in various fields such as quantum optics, photonics, plasmonics, and quantum information technology. Few of the phenomenon include, for instance, light storage, ultra-slow and ultra-fast propagation, optical transparency, and quantum entanglement via quantum coherence or superposition. The understanding of these phenomenon of milestone implications paved the way for the invention of novel classical and quantum technology. In this article, we present detailed theoretical and numerical demonstration on the dispersion-dependent phenomenon of slow and fast light, optically induced transparency, and photon drag. For this, we employ a three-level scheme of an ensemble of GaAs\\AlGaAs double quantum dot molecule in cascade configuration. In particular, by tuning the medium dispersion we predict interesting interplay between ultra-slow and ultra-fast light propagation with vanishing, infinite, ultra-positive and ultra-negative group velocities, and optical-assisted quantum transparency. The quantum coherence of the dressed states modifies considerably the optical properties of the system in view of dispersion, absorption, electron energy loss, transmission, and photon drag. An interesting interplay between ultra-slow to ultra-fast propagation is found by tuning various optical parameters. The calculated superluminal value of group velocity is m s−1. We also predict light propagation at vanishing and infinite group velocity. The calculated light drag is rad/m.

Effects of dual cross Kerr non-linearity on the manipulation of rotary photon drag

Effects of dual cross Kerr non-linearity on the manipulation of rotary photon drag

Sagnac interferometry and self-Kerr nonlinearity dependent photon drag

We present a theoretical investigation of the photon drag by incorporating self-Kerr nonlinearity (SKN) in a Sagnac interferometer featuring a four-level atomic system. By introducing SKN in the system, we demonstrate significant improvements in the photon drag angles, ranging from ±10 micro-radians to ±1 centi-radians. Additionally, the presence of SKN leads to electromagnetically induced transparency (EIT), reduced group velocities, and a positive group index enhancement within the system. Conversely, in the absence of SKN, a negative group index is observed, accompanied by larger group velocities and minimal photon drag angles. The results obtained may have potential applications in various fields, such as slow-light detection, controlled image coding/design, efficient light modulators, and phase-matching in Brillouin scattering.

Electric Control of Helicity-Dependent Photocurrent and Surface Polarity Detection on Two-Dimensional Bi2O2Se Nanosheets.

Bismuth oxyselenide (Bi2O2Se) is a two-dimensional (2D) layered semiconductor material with high electron Hall mobility and excellent environmental stability as well as strong spin-orbit interaction (SOI), which has attracted intense attention for application in spintronic and spin optoelectronic devices. However, a comprehensive study of spin photocurrent and its microscopic origin in Bi2O2Se is still missing. Here, the helicity-dependent photocurrent (HDPC) was investigated in Bi2O2Se nanosheets. By analyzing the dependence of HDPC on the angle of incidence, we find that the HDPC originates from surface states with Cs symmetry in Bi2O2Se, which can be attributed to the circular photogalvanic effect (CPGE) and circular photon drag effect (CPDE). It is revealed that the HDPC current almost changes linearly with the source-drain voltage. Furthermore, we demonstrate effective tuning of HDPC in Bi2O2Se by ionic liquid gating, indicating that the spin splitting of the surface electronic structure is effectively tuned. By analyzing the gate voltage dependence of HDPC, we can unambiguously identify the surface polarity and the surface electronic structure of Bi2O2Se. The large HDPC in Bi2O2Se nanosheets and its efficient electrical tuning demonstrate that 2D Bi2O2Se nanosheets may provide a good platform for opto-spintronics devices.

Giant photon momentum locked THz emission in a centrosymmetric Dirac semimetal.

Strong second-order optical nonlinearities often require broken material centrosymmetry, thereby limiting the type and quality of materials used for nonlinear optical devices. Here, we report a giant and highly tunable terahertz (THz) emission from thin polycrystalline films of the centrosymmetric Dirac semimetal PtSe2. Our PtSe2 THz emission is turned on at oblique incidence and locked to the photon momentum of the incident pump beam. Notably, we find an emitted THz efficiency that is giant: It is two orders of magnitude larger than the standard THz-generating nonlinear crystal ZnTe and has values approaching that of the noncentrosymmetric topological material TaAs. Further, PtSe2 THz emission displays THz sign and amplitude that is controlled by the incident pump polarization and helicity state even as optical absorption is only weakly polarization dependent and helicity independent. Our work demonstrates how photon drag can activate pronounced optical nonlinearities that are available even in centrosymmetric Dirac materials.