Document Type : Research

Authors

• Mohsen Ruzbehani ¹
• naser Partovi Shabestari ²
• hamid Ghaemi Bafghi ³

¹ Photonic and Quantum Technologies Research School, Nuclear Science and Technology Research Institute, Tehran, Iran.

² Photonic and Quantum Technologies Research School, Nuclear Science and Technology Research Institute, Tehran,

³ M. Sc. Graduated, School of physics, Iran University of Science & Technology, Tehran, Iran.

Abstract

Holographic diffraction gratings play a key role as dispersive optical elements in spectrometers, diode lasers, optical filters, and communication systems. This paper presents the design and development of an active stabilization system for maintaining the stability of interference fringes during the recording process of holographic gratings. In holographic setups, interference fringes are susceptible to displacement due to factors such as environmental vibrations, temperature fluctuations, air currents, and laser source instability. Some of these disturbances, particularly random vibrations, can only be effectively managed using active control methods. In this paper, an active feedback system based on a PID controller is employed to stabilize the interference fringes. The fringes are detected using a CCD camera, and after software-based analysis, the displacement is compensated by adjusting the path of one of the laser beams using a piezoelectric actuator attached to a mirror. The piezoelectric device is controlled by applying an appropriate voltage. This method is capable of reducing environmental fluctuations to approximately λ/24 (for a wavelength of 442 nm), equivalent to about 18 nanometers.

Keywords

• Holographic diffraction grating
• Interference stabilization
• PID controller
• Piezoelectric mirror
• Optical feedback