Speckle- and interference fringes-free illumination system with a multi-retarder plate.

Our study proposes a novel method for obtaining speckle-free homogeneous illumination using a combination of a multi-retarder plate, a microlens array, a Fourier lens, and a diffraction optical element (DOE) based on pseudorandom binary sequences. The proof-of-concept multi-retarder plate is introduced to generate multiple uncorrelated laser beams, while a mathematical model was developed to explain the method's mechanism and evaluate its effectiveness. In the DOE passive (stationary) mode, the method was found to reduce speckle contrast to 0.

Combined small and large magnetic nanoparticle extraction and concentration from biofluids for non-toxic detection of biomarkers.

We propose a novel non-toxic method of diagnostic biomarker extraction and concentration from biofluids. The method is based on the usage of (1) magnetic nanoparticles of a few nanometres in size bearing molecular traps for biomarkers on their surface and (2) additional larger (several tens of nanometres) magnetic nanoparticles for catching smaller magnetic nanoparticles in a strong magnetic field gradient with their consequent concentration into the detection area. It is shown that the interference of an external permanent gradient magnetic field with the magnetic field of large magnetic nanoparticles allows one to catch small magnetic nanoparticles from their trajectories in a fluid at a distance around ten radii of the large nanoparticles.

Investigation of speckle suppression beyond human eye sensitivity by using a passive multimode fiber and a multimode fiber bundle.

A method of speckle suppression without any active device is expected for pico-projectors. The effectiveness of the passive method of speckle reduction using a single multimode fiber and a multimode fiber bundle was actually measured and theoretically analyzed. The dependences of the speckle contrast and speckle suppression coefficient on the parameters of multimode fiber and projection systems were investigated.

Optical plasmon nanostrip probe as an effective ultrashort pulse delivery system.

In this paper, we analyze the ultrafast temporal and spectral responses of optical fields in tapered and metalized optical fibers (MOFs) and optical plasmon nanostrip probes (NPs). Computational experiment shows that output pulses of the NPs are virtually unchanged in shape and duration for input pulses with a duration of >1 fs and are not sensitive to changes in the parameters of the probe (such as convergence angle and taper length), while local enhancement of the electric field intensity reaches 300 times at the NP apex. Compared with the NPs, MOFs lead to significant output pulse distortions, even for input pulses with a duration of 10 fs.

Experimental demonstration of a flexible DOE loop with wideband speckle suppression for laser pico-projectors.

The compact and straightforward construction of a pico-projector using an original method for speckle suppression via a simple 1D diffractive optical element (DOE) structure on a loop of flexible film with tracked motion is demonstrated. The 1D-DOE structure is based on binary pseudorandom sequences. The method requires very little energy and space and can decrease speckle noise to levels below the detection sensitivity of the human eye.