The interferometer for microsecond high-speed phenomena

The state of the art interferometer “DELTAPH” sustained by our unique High speed polarization camera “CRYSTA”. The system can measure phase shift image from one snapshot fringe image without mechanical scanning. Its high-speed and real-time capabilities allow the evaluation of fast-moving dynamic phenomena.

Conventional interferometers mechanically scan the reference mirror, so there is a limitation of frame rate, and they cannot measure instantaneous phenomena in one shot. However, our DELTAPH interferometer is now capable of one-shot measurement without mechanical drive by our proprietary polarization measurement technology.

Sound field imaging is one of the applications that requires high-speed and one-shot measurement. One-shot measurement is essential because sound travels through the air at a speed of 340 meters per second. Shutter speed of the DELTAPH interferometer is 1 microsecond or less with over 7,000 phase images per second. It’s possible to visualize sound propagation through the air without blur. Moreover, we have possibility of analyzing variation of related air density by sound travel because the image has quantitative phase information.
For other applications, It can measure slight change of surface shape cause of vibration or impact when the sample is placed instead of the reference mirror.

Propagation of 40kHz Sound Waves

Frame rate:100,000 FPS
sound pressure:>110dB

Visualization of the Sound Propagating from Castanets

Frame rate:100,000 FPS

At the moment of the impact, we can see a strong, high-frequency spike (very narrow blue stripe near the impact zone) in the distribution.

After a few milliseconds, the frequency gradually decreases (stripe getting wider while propagating from the impact zone) and the wave decays.

Key Differences with Conventional Interferometers

To measure the shape of an object, indirectly measured as surface “phase”, with an interferometer, we traditionally use a reference surface whose position needs to be adjusted and scanned during the measurement, making the whole process not suitable for moving objects, especially at high speeds.

Conventional interferometer needs scanning of the mirror

The DELTAPH possibles to measure phase image by one-shot usning our polarization camera.


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