A 5kHz modulator for pyramid wavefront sensors

Fuente: arXiv
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Autores principales: Häberle, Maximilian, Naranjo, Vianak, Reinarz, Yared, Feldt, Markus, Scheithauer, Silvia, Bertram, Thomas, Bramigk, Arne, Marth, Harry
Formato: Preprint
Publicado: 2026
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author Häberle, Maximilian
Naranjo, Vianak
Reinarz, Yared
Feldt, Markus
Scheithauer, Silvia
Bertram, Thomas
Bramigk, Arne
Marth, Harry
author_facet Häberle, Maximilian
Naranjo, Vianak
Reinarz, Yared
Feldt, Markus
Scheithauer, Silvia
Bertram, Thomas
Bramigk, Arne
Marth, Harry
contents Despite the emergence of new types of wavefront sensors, the modulated pyramid wavefront sensor remains the workhorse for ELT instrumentation, and is among the options even for advanced high-contrast, high-Strehl instrumentation like PCS and SAXO+. To achieve the required degree of wavefront control, an operation at frequencies of 3kHz, ideally up to 5kHz, is necessary, requiring an optomechanical device capable of delivering accurate circular modulation patterns with these frequencies. Here, we present tests of a novel type of high-frequency modulator based on shearing piezo actuators. The modulator prototype moves a flat circular mirror (15mm diameter) with a tip-tilt range of plus/minus 50 arcsec. At a typical 10mm pupil diameter on the modulator mirror, and operating at 2.2$μ$m, this will create a modulation circle with a radius of slightly greater than 2 $λ$/D. While this is less than conventionally specified for most instruments, it should already be sufficient for any practical application except for very bad conditions or extended targets. We performed modulation tests at frequencies between 250 Hz to 5 kHz using a test setup including a modulated laser beam probed with a high-speed camera. The prototype showed stable behaviour during a one-hour-long operation at a maximum frequency of 5 kHz and with negligible heat generation. The maximum modulation amplitude was 60 arcsec. We observed very accurate reproduction of the input modulation pattern with typical ellipticities less than 1% and random deviations below 0.2% for frequencies below 4.5kHz. These tests demonstrate the prototype's capabilities and could be followed by on-sky tests or the integration of the modulator into XAO testbeds.
format Preprint
id arxiv_https___arxiv_org_abs_2603_15748
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle A 5kHz modulator for pyramid wavefront sensors
Häberle, Maximilian
Naranjo, Vianak
Reinarz, Yared
Feldt, Markus
Scheithauer, Silvia
Bertram, Thomas
Bramigk, Arne
Marth, Harry
Instrumentation and Methods for Astrophysics
Despite the emergence of new types of wavefront sensors, the modulated pyramid wavefront sensor remains the workhorse for ELT instrumentation, and is among the options even for advanced high-contrast, high-Strehl instrumentation like PCS and SAXO+. To achieve the required degree of wavefront control, an operation at frequencies of 3kHz, ideally up to 5kHz, is necessary, requiring an optomechanical device capable of delivering accurate circular modulation patterns with these frequencies. Here, we present tests of a novel type of high-frequency modulator based on shearing piezo actuators. The modulator prototype moves a flat circular mirror (15mm diameter) with a tip-tilt range of plus/minus 50 arcsec. At a typical 10mm pupil diameter on the modulator mirror, and operating at 2.2$μ$m, this will create a modulation circle with a radius of slightly greater than 2 $λ$/D. While this is less than conventionally specified for most instruments, it should already be sufficient for any practical application except for very bad conditions or extended targets. We performed modulation tests at frequencies between 250 Hz to 5 kHz using a test setup including a modulated laser beam probed with a high-speed camera. The prototype showed stable behaviour during a one-hour-long operation at a maximum frequency of 5 kHz and with negligible heat generation. The maximum modulation amplitude was 60 arcsec. We observed very accurate reproduction of the input modulation pattern with typical ellipticities less than 1% and random deviations below 0.2% for frequencies below 4.5kHz. These tests demonstrate the prototype's capabilities and could be followed by on-sky tests or the integration of the modulator into XAO testbeds.
title A 5kHz modulator for pyramid wavefront sensors
topic Instrumentation and Methods for Astrophysics
url https://arxiv.org/abs/2603.15748