Read spectra

The examples below show how to read out different types of spectra from the Monipa 1 and give more information on how they are acquired. We recommend using the regions from 900 cm⁻¹ to 2000 cm⁻¹ for most applications. Outside of this range, the signal-to-noise ratio can be too low for reliable analysis.

AbsorbanceRaw EnergyWavenumbersInterferogram

Read out the current absorbance spectrum

import requests

mode = "standard_v2"  # processing mode

response = requests.get(
    f"http://10.0.0.2:5555/api/spectrometer/spectra/processed/{mode}",
    params={
        "n_scans": 5,
    },
).json()

print(f"Absorbance: {response}")

When requesting an absorbance spectrum, you can change number of scans to average via the parameter n_scans. You can also request different processing modes.

• standard_v2: Processing with drift stabilization.
• evaluation: Fast processing.

In the next section, we will use the spectra read endpoints for an interactive plot.

Read out the current raw energy spectra

import requests

response = requests.get(
    "http://10.0.0.2:5555/api/spectrometer/spectra/averaged/standard_v2",
    params={
        "n_scans": 5,
    },
).json()

p, s = response
print("Polarization spectra:")
print(f"P energies: {p}")
print(f"S energies: {s}")

Note

You can also request the raw energy spectrum via the endpoint /api/spectrometer/spectra/averaged. This returns the energies without any optical calibration at a specific polarization angle. These can be set using the endpoint /api/microcontroller/polarizer/steps.

Get the wavenumbers associated with the spectrometer resolution

import requests

response = requests.get(
    "http://10.0.0.2:5555/api/spectrometer/wavenumbers",
).json()

print(f"Wavenumbers: {response}")

The wavenumbers depend on the spectrometer resolution setting. You can change the resolution via the endpoint PUT /api/spectrometer/resolution.

For the default resolution of 3.5 cm⁻¹, the wavenumbers range from approximately 834 cm⁻¹ to 5000 cm⁻¹, with a step size of 1.75 cm⁻¹.

[  
    834.75,
    836.5,
    838.25,
    ...
    4996.25,
    4998.0,
    4999.75
]

Read out the current interferogram

import requests

response = requests.get(
    "http://10.0.0.2:5555/api/spectrometer/interferogram",
).json()

print(f"Interferogram size: {len(response)}")
print(f"Interferogram: {response}")

You can also request the displacements via the endpoint /api/spectrometer/interferogram/displacements.