matrix_slm

Raghav K. Chhetri

Phase Retrievel via Gerchberg-Saxton algorithm to generate phase masks for Meadowlarks HSP1920 SLM in the Matrix microscope

Using "LightPipes for Python"

Usage

1. To generate a small number of user-defined patterns, use GerchbergSaxton_Matrix.ipynb. It calls the following modules:

   a. target_pattern() to define target pattern. Available selections are as follows-

   MATRIX

   FAR, FAR_beam1, FAR_beam4, FAR_beam7

   MID, MID_beam2, MID_beam5, MID_beam8

   NEAR, NEAR_beam3, NEAR_beam6, NEAR_beam9

   DIAGONAL i.e., beams 1-5-9

   It also allows the position of each beam to be manually defined via the movebeams_um parameter, which follows this convention-

    movebeams_um = [beam1, beam2, beam3,
                    beam4, beam5, beam6,
                    beam7, beam8, beam9]
    where
    far = beams1-4-7
    mid = beams2-5-8
    near = beams3-6-9  
    
    Note: +ve values for `movebeams_um` moves the beam UP in sample space 
    i.e., along +Z in the Matrix microscope       
   

   b. generate_mask()to compute phase mask as .bmp, which when applied to the SLM generates its corresponding target pattern

   ---

2. To generate a large batch of patterns for a grid of beam positions (see rules below), use GerchbergSaxton_Matrix_MultiProcess.ipynb. It calls the following modules:

   a. move_func() to auto-generate a list of beam positions to run multiprocessing on

   b. mask_func() to compute phase mask for each beam position.

   c. target_func() to define target pattern for each beam position. All above target pattern selections are available

   Rules for beam positions on a 3x3 grid:
   - Each beam has two choices: 0 or +step, then 2^9 = 512 combinations
   - Each beam has two choices: 0 or -step (511 combinations: all zeros is already counted)
   - Each beam has two choices: +step or -step (510 combinations: all +step and all -step already counted)
   So, only considering 1533 combinations out of possible 3^9 combinations