arXiv subjects

Bahareh Mastiani

Publications and source records attributed to Bahareh Mastiani.

4 recordsLinked to original sources

arXiv2026

3D scanning microscopy through scattering surfaces using the optical memory effect

Wavefront shaping allows light to be focused through scattering objects. However, the wavefront correction found is only valid in a small region called the isoplanatic patch. Here we present a simple approach to extend this isoplanatic patch by shifting and scaling the corrected wavefront appropriately, demonstrating an 8.6-fold increase in the lateral scanning range and a 1.5-fold increase in the axial range through a scattering layer without the need to perform additional wavefront shaping measurements. Our findings agree well with a simple geometrical model that also allows us to extract the effective position of the scattering layer from the measurements.

physics.optics↗

arXiv2024

Practical considerations for high-fidelity wavefront shaping experiments

Wavefront shaping is a technique for directing light through turbid media. The theoretical aspects of wavefront shaping are well understood, and under near-ideal experimental conditions, accurate predictions for the expected signal enhancement can be given. In practice, however, there are many experimental factors that negatively affect the outcome of the experiment. Here, we present a comprehensive overview of these experimental factors, including the effect of sample scattering properties, noise, and response of the spatial light modulator. We present simple means to identify experimental imperfections and to minimize their negative effect on the outcome of the experiment. This paper is accompanied by Python code for automatically quantifying experimental problems using the OpenWFS framework for running and simulating wavefront shaping experiments.

physics.optics↗

arXiv2021

Noise-tolerant wavefront shaping in a Hadamard basis

Light scattering is the main limitation for optical imaging. However, light can be focused through or inside turbid media by spatially shaping the incident wavefront. Wavefront shaping is ultimately limited by the available photon budget. We developed a new `dual reference' wavefront shaping algorithm that optimally uses the available light. Our method allows for multi-target wavefront shaping, making it suitable for transmission matrix measurements or transmitting images. We experimentally confirmed the improvement of the focus intensity compared to existing methods.

physics.ins-det↗

arXiv2019

Scanning a focus through scattering media without using the optical memory effect

Wavefront shaping makes it possible to form a focus through opaque scattering materials. In some cases, this focus may be scanned over a small distance using the optical memory effect. However, in many cases of interest, the optical memory effect has a limited range or is even too small to be measured. In such cases, one often resorts to measuring the full transmission matrix (TM) of the sample to completely control the light transmission. However, this process is time-consuming and may not always be possible. We introduce a new method for focusing and scanning the focus at any arbitrary position behind the medium by measuring only a subset of the transmission matrix, called Sparse Field Focusing (SFF). With SFF, the scan range is not limited to the memory effect and there is no need to measure the full transmission matrix. Our experimental results agree well with our theoretical model. We expect this method will find applications in imaging through scattering media, especially when the optical memory effect range is small.

physics.optics↗