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Magnetic Field Sweep and Spatial Mapping Automation

Author: Serdar (adjusted by Lukas and Ryan)
Last Updated: April 2025
Filename: Mag_Field_Sweep_2024_10_21.py

Overview

This script automates spectral acquisition in a magneto-optical experiment using:

LightField for spectrometer control (Princeton Instruments)
AMC Positioner for precise spatial scanning
Attocube APS100 power supplies for magnetic field control

It enables:

Magnetic field sweeps along selected axes
Spatial scans across X-Y positions
B-field vector rotations with spectral capture
Live spectrum acquisition and intensity mapping

Features

2D Spatial Scan: Raster-scan across a surface using AMC positioners, capturing spectra at each coordinate.
Magnetic Field Sweep: Vary B-fields in controlled steps along x/y/z, measure spectra at each step.
Field Rotation: Circular B-field rotation (in-plane) with angle-defined steps.
Automated File Handling: Acquires .spe files, extracts and saves intensity/wavelengths, deletes intermediates.
Flexible Configuration: Resolution, range, exposure, filters, filenames and scan directions are all customizable.

Prerequisites

Hardware

AMC100/AMC300 positioner
Attocube APS100 single/dual-channel magnet power supplies
Spectrometer compatible with Princeton Instruments LightField

Software & Libraries

Python 3.8+
Packages: pyvisa, numpy, matplotlib, pandas, clr, spe2py, spe_loader, AMC module
.NET integration via pythonnet
LightField SDK: Princeton Instruments (with DLLs loaded via clr)

Note: Ensure LIGHTFIELD_ROOT environment variable is set.

Setup

Install dependencies

pip install pyvisa pandas numpy matplotlib pythonnet

Ensure required DLLs are present in:

C:\Program Files\Princeton Instruments\LightField\

Set up device IPs

IP_AMC100 = "192.168.71.100"  # or AMC300

Edit scan parameters in main block:

range_x = 20000
range_y = 20000
resolution = 1000  # nanometers

set_llim_bval = -0.3
set_ulim_bval = 0.3
set_res_bval = 0.003  # Tesla

Main Functions

`move_scan_xy(range_x, range_y, resolution, Settings, baseFileName)`

Performs a 2D XY raster scan of the probe. Acquires spectra and saves results.

`sweep_b_val(instr, min_bval, max_bval, res, axis, Settings, base_file_name)`

Sweeps magnetic field (in T) along the specified axis, collecting spectra at each field.

`ramp_b_val(instr, bval, magnet_coil)`

Smooth ramping of B-field to target value.

`b_field_rotation(instr1, instr2, Babs, startangle, endangle, step, Settings)`

Rotates the in-plane magnetic field by vector combination of Bx and By components.

File Saving

.txt: Intensity data and wavelength arrays saved to timestamped folders
Folder names include experiment metadata
.spe files are deleted after processing to conserve space

Usage Example

To sweep B-field along the Y-axis:

sweep_b_val(
    instr=powerbox_singlesupply,
    min_bval=-0.3,
    max_bval=0.3,
    res=0.003,
    magnet_coil='y-axis',
    Settings='experiment_config',
    base_file_name='scan_name',
    zerowhenfin_bool=True,
    reversescan_bool=False,
    loopscan_bool=True
)

Notes

Always close power supply connections with .close()
Make sure .spe files are not locked by LightField before running
The AMC section is currently commented — uncomment if positioner control is needed
Ensure experiment.Load(...) points to the correct .lfe config

Troubleshooting

DLL loading issues? Confirm path via sys.path.append(...) and DLL names.
Communication errors? Check serial port resource names via pyvisa.ResourceManager().list_resources()
No spectra saved? Ensure LightField is licensed and experiment file is valid.

License

Internal use only – please contact the authors before distribution or reuse.

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