Real-Time Correction and Stabilization of Laser Diode Wavelength in Miniature Homodyne Interferometer for Long-Stroke Micro/Nano Positioning Stage Metrology

Abstract

A low-cost miniature homodyne interferometer (MHI) with self-wavelength correction and self-wavelength stabilization is proposed for long-stroke micro/nano positioning stage metrology. In this interferometer, the displacement measurement is based on the analysis of homodyne interferometer fringe pattern. In order to miniaturize the interferometer size, a low-cost and small-sized laser diode is adopted as the laser source. The accuracy of the laser diode wavelength is real-time corrected by the proposed wavelength corrector using a modified wavelength calculation equation. The variation of the laser diode wavelength is suppressed by a real-time wavelength stabilizer, which is based on the principle of laser beam drift compensation and the principle of automatic temperature control. The optical configuration of the proposed MHI is proposed. The methods of displacement measurement, wavelength correction, and wavelength stabilization are depicted in detail. A laboratory-built prototype of the MHI is constructed, and experiments are carried out to demonstrate the feasibility of the proposed wavelength correction and stabilization methods.

Rhinitis phototherapy prototype with timer based on light energy

“…The average measurements for the right laser were found to be 652.4 nm, while for the left laser, it was 653.23 nm. These measurements were influenced by factors such as room lighting, the precision of laser diode placement, and the measuring instrument used [20] [22]. It is worth noting that the specifications of laser diodes available in the market can vary, resulting in slight differences in wavelength, such as 2.4 nm for the right laser and 3.23 nm for the left laser.…”

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“…Optical methods include laser interferometers and grating interferometers, both capable of high measurement accuracy, albeit with certain limitations in their applications. On the one hand, laser interferometers excel in controlled environments like laboratories, where the laser wavelength remains stable and measurement accuracy is exceptionally high [6][7][8][9][10][11][12]. On the other hand, grating interferometers are preferred in scenarios where environmental conditions cannot be precisely controlled [13][14][15][16].…”

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