Phase and amplitude reconstruction in single-pixel transmission microscopy: a comparison of Hadamard, cosine, and noiselet bases

Hadamard, cosine, and noiselet bases are implemented into a digital holographic microscope based on single-pixel imaging with the capability to retrieve images of complex objects. The object is illuminated with coherent light modulated with different patterns deployed in a digital micromirror device, and the resulting fields are captured by single-pixel detection. For amplitude images, the experimental results of the three bases are evaluated with the peak SNR criteria. It is shown that the cosine basis recovers amplitude distributions with the best quality. Regarding phase images, the recovered ones compare well with those obtained with a CMOS camera.

Use of polar decomposition of Mueller matrices for optimizing the phase response of a liquid-crystal-on-silicon display

We provide experimental measurement of the Mueller matrices corresponding to an on-state liquid-crystal-on-silicon display as a function of the addressed voltage. The polar decomposition of the Mueller matrices determines the polarization properties of the device in terms of a diattenuation, a retardance and a depolarization effect. Although the diattenuation effect is shown to be negligible for the display, the behavior of the degree of polarization as a function of the input polarization state shows a maximum coupling of linearly polarized light into unpolarized light of about 10%. Concerning the retardation effect, we find that the display behaves as a retarder with a fast-axis orientation and a retardance angle that are voltage-dependent. The above decomposition provides a convenient framework to optimize the optical response of the display for achieving a phase-mostly modulation regime. To this end, the display is sandwiched between a polarization state generator and a polarization state analyzer. Laboratory results for a commercial panel show a phase modulation depth of 360 masculine at 633 nm with a residual intensity variation lower than 6 %.

Low-frequency and high-frequency all-fiber modulators based on birefringence modulation

In-line optical modulators with low insertion losses and high maximum optical powers are required for Q switching and cavity dumping of fiber lasers as well as for nonlinear optical-fiber experiments. We report the design of polarimetric all-fiber modulators based on optical-fiber birefringence modulation combined with an all-fiber polarizer. Birefringence modulation involves a piezoelectric ceramic tube. This simple technique permits efficient low-frequency and high-frequency harmonic modulation, up to the megahertz range, as well as modulation of pulses shorter than 1 micros.