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Hybrid optical fibers have been widely investigated in different architectures to build integrated fiber photonic devices and achieve various applications. Here we proposed and fabricated hybrid microfiber waveguides with self-growing polymer nanofilms on the surfaces of microfibers triggered by evanescent field of light for the first time. We have demonstrated the polymer nanofilm of ∼50 nm can be grown on the microfiber with length up to 15 mm. In addition, the roughness of nanofilm can be optimized by controlling the triggering laser power and exposure duration, and the total transmission loss of the fabricated hybrid microfiber is less than 2 dB within a wide wavelength range. The hybrid polymer nanofilm microfiber waveguides have been characterized and their relative humidity (RH) responses have also been tested, indicating a potential for RH sensing. Our fabrication method may also be extended to construct the hybrid microfibers with different functional photopolymer materials.We report a quasi-continuous beam splitter with highly efficient equal-power beam splitting in a wide spectral range. It consists of rhombic aluminum antimonide nanorods standing on a silica substrate. Firstly, a beam splitter based on discrete structures is designed, and the structures are optimized to obtain the quasi-continuous beam splitter. The beam splitter achieves a splitting efficiency of over 80% within the region of 675-786 nm (bandwidth = 111 nm), where the splitting angle can vary in the range of 97.2°-121.8°. In particular, the splitting efficiency reaches 93.4% when the wavelength is 690 nm. MEK inhibitor drugs Overall, the proposed beam splitter potentially paves the way for realizing broadband metasurfaces and high-performance quasi-continuous metasurface-based devices.This paper investigated the effects of femtosecond laser beam polarization on ablation efficiency and microstructure symmetricity for 64FeNi alloy (Invar) sheet processing to fabricate fine metal masks. It was found that the ablation efficiency for linear polarization was approximately 15% higher than that for circular polarization due to electric field enhancement induced by low-spatial-frequency laser-induced periodic surface structures (LIPSS). The hole size and sidewall taper angles for the microstructures generated by linear polarization were asymmetric, whereas those generated by circular polarization were symmetric due to non-oriented LIPSS. The asymmetric and symmetric three-dimensional microstructure profiles, measured by using a confocal laser scanning microscope, were verified by employing an analytical model that was derived using the total input fluence and the ablation rates for linear and circular polarizations, respectively.Based on the fracture mechanics and grinding kinematics, a theoretical model is developed to determine various subsurface damage (SSD) parameters and roughness Rz of the ground brittle material with consideration of the material removal mode and spring back. Based on the image processing, a digital method is proposed to extract various SSD parameters from the cross-section micrograph of the ground sample. To verify the model and method, many fused silica samples are ground under different processing parameters, and their SSD depth and roughness Rz are measured. The research results show the average SSD depth (SSDa) can be expressed as SSDa = χ1Rz4/3 + χ2Rz (χ1 and χ2 are coefficients). The SSDa is closer to half of the maximum SSD depth (SSDm) as the wheel speed decreases or the grinding depth, feed speed, or abrasive diameter increases. The SSD length or density basically increases linearly with the increase of the SSDm. The digital method is reliable with a largest relative error of 6.65% in SSD depth, extraction speed of about 1.63s per micrograph, and good robustness to the micrograph size and small-scale residue interference. The research will contribute to the evaluation of SSDs and the optimization of the grinding process of fused silica.Phase-shifting fringe projection profilometry is a widely used and important technique for three-dimensional surface measurement, where N-step fixed-step phase-shifting algorithms are commonly used. With a pressing need to apply this technique for dynamic object/scene measurement, the motion-induced error poses a challenge in achieving high measurement accuracy. A few correction methods have been developed by involving physical markers or complicated algorithms. In this paper, the equal-step phase-shifting algorithms are proposed as a simpler yet more effective solution. By approximating the phase variations as unknown but linear phase shifts, the equal-step algorithms are naturally immune to object motion. In particular, two classical algorithms, including the four-step Carré algorithm and the five-step Stoilov algorithm, are adopted. Furthermore, a novel three-step gradient-based equal-step phase-shifting (GEPS) algorithm is proposed. These equal-step algorithms are studied through comprehensive simulations and experiments, showing that, (i) the equal-step algorithms are all effective in greatly suppressing the motion-induced errors in both ideal and noisy situations; and (ii) among the three algorithms, the Stoilov algorithm is more robust to handle the object motion and the harmonics simultaneously, while the GEPS requires a least number of frames. This study will urge the use of the equal-step algorithms for phase extraction in dynamic profilometry for immediate motion-error suppression by merely implementing a single phase-calculation equation.This work systematically investigates the third-order nonlinear optical (NLO) properties and ultrafast carrier dynamics of layered indium selenide (InSe) obtained by mechanical exfoliation (ME). The two-photon absorption (TPA) effect of layered InSe was tested using micro-Z/I-scan techniques. The results indicate that InSe flakes undergo the TPA response under the excitation of both 520 nm and 1040 nm fs pulses, and that InSe is more likely to achieve TPA saturation under visible light excitation. Furthermore, ultrafast carrier dynamics revealed that InSe flakes in the visible region undergo a transition from photoinduced absorption to photobleaching and exhibit a fast recombination time of ∼0.4-1ps, suggesting a high optical modulation speed as high as ∼1-2.5 THz.In the present work, we propose a programmable multiplexed grating-based wavefront sensor (MGWS) to realise zonal and modal wavefront sensing approaches simultaneously. This is implemented by employing different bit-planes of a color image such that zonal wavefront sensing is performed with enhanced spatial resolution and modal wavefront sensing is performed to measure a large number of aberration modes present in the incident wavefront, simultaneously. We present proof-of-concept simulation results that demonstrate the working of the proposed MGWS and its ability to compensate for the presence of large number of aberration modes significantly, in comparison to either of the sensing approaches when used independently. Further, simulation results are included to quantify the same by considering an optical imaging system to image an array of two-dimensional bead objects. The proposed sensor is flexible in easy switching between either of the sensing approaches and the number of bit-planes can be increased conveniently to further improve the performance of the proposed MGWS.Al0.85Ga0.15As0.56Sb0.44 is a promising avalanche material for near infrared avalanche photodiodes (APDs) because they exhibit very low excess noise factors. However electric field dependence of ionization coefficients in this material have not been reported. We report a Simple Monte Carlo model for Al0.85Ga0.15As0.56Sb0.44, which was validated using reported experimental results of capacitance-voltage, avalanche multiplication and excess noise factors from five APDs. The model was used to produce effective ionization coefficients and threshold energies between 400-1200 kV.cm-1 at room temperature, which are suitable for use with less complex APD simulation models.Residual amplitude modulation is one of the major sources of instability in many precision measurements using frequency modulation techniques. Although a transverse and inhomogeneous distribution of residual amplitude modulation has long been observed, the underlying mechanism is not well understood. We perform measurement and analysis of this spatial inhomogeneity using several electro-optic crystals of different types. Two distinct components are identified in the spatial distributions, and their detailed properties, some of which are previously unnoticed, are mapped out and analyzed, showing that the spatial inhomogeneity can be explained by acousto-optic interaction inside the crystal. Moreover, this spatial inhomogeneity can be further suppressed, improving the 1000-s stability of residual amplitude modulation to 3×10-7 (8×10-8) at modulation frequency of 11 MHz (120 kHz), corresponding to a frequency instability of 1×10-17 (3×10-18), estimated for a cavity-stabilized laser using a Pound-Drever-Hall discrimination slope of 1×10-4 V/Hz.Counter-propagating ultrafast pulses can disrupt the phase of harmonic generation, and offer a means to achieve quasi-phase matching in processes like high-order harmonic generation. Optimizing this process requires accurate modeling. Using second harmonic generation (SHG) as a simpler and more accessible proxy, we compare the results of two numerical simulations to experimental measurements of SHG with counter-propagating pulses. The first follows previous theoretical work in assuming a quasi-CW pulse and solving the nonlinear wave equation in the time-domain. However, we find that adapting a frequency-domain model to account for the broadband nature of ultrafast pulses better reproduces the salient features we observe in our experimental results.Computational ghost imaging (CGI) uses preset patterns and single-pixel detection, breaking through the traditional form of point-to-point imaging. In this paper, based on the Monte Carlo model, a reflective polarization based CGI (PCGI) system has been proposed and constructed under the foggy environments. And the imaging performances of the PCGI at different optical distances have been investigated and analyzed quantitatively. When the targets and the background have a small difference in reflectivity, the difference of polarization characteristics between the targets and the background can help the CGI to remove the interference of scattering light and improve the imaging contrast. Besides, in order to further improve imaging efficiency, a scanning-mode polarization based CGI (SPCGI) has also been proposed, in which the combination of polarization characteristics and the scanning-mode plays an important role to improve the CGI's imaging efficiency and imaging quality.Recent studies have demonstrated that multilayer transition metal dichalcogenides can serve as promising building blocks for creating new kinds of resonant optical nanostructures due to their very high refractive indices. However, most of such studies have focused on excitonic regimes of light-material interaction, while there are few on the low-loss region below the bandgap. Here, we conceptually propose all-van der Waals photonic crystals made of electronically bulk MoS2 and h-BN, designed to operate in the telecom wavelengths. And we demonstrate that, due to extremely low absorption loss and destructive interaction between symmetry-protected and resonance-trapped bound states in the continuum, high-quality factor transmission peaks associated with electromagnetically induced transparency (EIT) are observed, thus rendering our proposed structures highly useful for applications like slow light and optical sensing. Furthermore, EIT-like effects are demonstrated in well-engineered MoS2 nanostructures with broken symmetry.