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A readout using a frequency-chirped laser is investigated in a spectrum analyzer with spectral-hole-burning (SHB). An analysis based on the Bloch equations is presented for the spectral distortion due to a fast readout, and a recovery algorithm is developed for the distortion. The experiment of a SHB spectrum analyzer is executed to demonstrate the optical spectral distortion due to fast readout. The experimental spectral distortion is recovered by the recovery algorithm developed from the Bloch equations.

We report on both the theoretical and experimental design of a black phosphorus (BP)-based reflective linear polarizer on Si/SiO 2 substrate in visible range using the Fabry-Perot cavities method. Thanks to the optical anisotropy of BP, polarization wavelength regulation and a high extinction ratio are achievable via optimizing the thickness of BP. Using azimuth-dependent reflectance difference microscopy, we directly measured a huge optical anisotropy of 1.58, corresponding to an extinction ratio of ∼9  dB, from a 96 nm BP on a silicon substrate capped by 260 nm thermally oxidized silicon at a wavelength of 690 nm for the first time, to the best of our knowledge. Our results not only provide a new route to designing nanoscale polarizers based on anisotropic two-dimensional (2D) materials, promoting the application of 2D materials in integrated optoelectronics and system-on-chip, but also suggest a modulation technique for optical anisotropy by integrating the BP film with cavity structures.

We propose liquid crystal variable retarder-based reflectance difference spectroscopy for normal-incidence measurements. Principles, instrumentation, data collection and reduction, and calibration procedures are provided. The signal noise is better than 10 -3 , and the spectral range is from 1.6 to 2.4 eV with 346 photon energy channels. As a demonstration, reflectance difference signals of a multilayer pentacene film on poly (ethylene terephthalate) (PET) film are presented with different polarization azimuths. The characteristic peaks at 1.8 and 1.97 eV, corresponding to the Davydov splitting of pentacene crystal, are observed, which indicate well-ordered in-plane anisotropic structure of pentacene crystal film on PET. Thanks to normal incidence, this design is immune to adjusting the optical structure for the measurements with different working distances, and the objective lens is easily integrated to realize microarea measurements.

We propose an approach to realize a high-quality optical conjugate of a piezo-driven mirror (PM) in optical tweezers. Misalignments between the optical beam and the steering center of the PM are analyzed mathematically. The decentrations in different directions cause different changes, either a position change of the conjugate plane or a spot variation of the beam during PM steering. On the other hand, these misalignment-introduced problems provide the information to check the assembling errors. Thus a wanted conjugate plane of the PM can be effectively and precisely achieved according to the detection signals. This approach is also available to deal with multifactor coupling error. At the end, the procedure for error analysis is given by testing homebuilt optical tweezers.

We present an approach for improving liquid crystal variable retarder (LCVR)-based spectroscopic polarization measurements. As deduced mathematically, the transfer coefficients from the random intensity noise to the signal noise are functions of modulation parameters of the LCVR, i.e., modulation range (MR) and initial retardation. Simulations allow more details about the roles of two parameters. A broad MR reduces effectively the values of the coefficients and leads to a better signal quality. However, as the MR narrows, initial retardation begins to influence the signal quality. To obtain a high-quality spectrum, a recommended solution is to settle the MR more than π at each wavelength. This treatment has two advantages: non-sinusoidal modulation becomes possible and the modulations do not average to zero. Moreover, it weakens the interference of non-uniform intensity distribution in wavelengths of the signal spectrum. These conclusions are proven in experiments. Further, this approach is valid for other polarimeters and ellipsometers based on LCVRs.

In this paper, we develop an analytical model of an integrated acousto-optical (AO) device with arms modulated by a single surface acoustic wave beam. A comparison between one-arm and two-arm modulation is presented, which shows that two-arm modulation can significantly enhance modulation efficiency by an optimized design. A detailed analysis of the influence of static phase difference on the behavior of the AO devices has been provided, and some interesting results have been obtained. These will be helpful for an optimized design of AO devices for different functionalities.

A composite of the conjugate conductive polymer poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene) (MEH-PPV) and CdSe/ZnS quantum dots (QDs) is utilized for nanoimprinted lasers after drop-casting onto one-dimensional omnidirectional Bragg mirrors. Strong amplified spontaneous emission is observed at the resonances of both the QDs and the polymer. Clearly resolved, low-threshold lasing was found after nanoimprinting of distributed-feedback gratings on the composite surface. Energy transfer between the polymer molecules and the QDs is demonstrated by excitation spectroscopy.