High-speed femtosecond laser beam shaping based on binary holography using a digital micromirror device

Area of Science:

• Optics and Photonics
• Laser Physics
• Nanotechnology

Background:

• Precise control over laser beam properties is crucial for advanced optical applications.
• Existing ultrafast beam shaping techniques often face limitations in speed, resolution, or flexibility.
• Digital micromirror devices (DMDs) offer potential for dynamic optical field manipulation.

Purpose of the Study:

• To introduce and demonstrate a novel DMD-based ultrafast beam shaper (DUBS).
• To achieve high-resolution, arbitrary laser beam mode generation at high repetition rates.
• To explore the capabilities of the DUBS for generating various beam profiles.

Main Methods:

• Utilizing a digital micromirror device (DMD) for binary beam shaping.
• Employing angular dispersion with a transmission grating and a mirror to compensate for dispersion.
• Programming the DMD with binary holography patterns to generate desired beam modes.
• Monitoring output beam modes with a CCD camera.

Main Results:

• The DUBS successfully generated high-resolution (1140×912 pixels) arbitrary beam modes, including Airy, Bessel, Laguerre-Gaussian (LG), and a custom 'peace-dove' beam.
• Demonstrated high-speed beam shaping by alternately generating Airy and LG beams at 4.2 kHz, limited by the DMD's pattern rate.
• Achieved an overall system efficiency of 4.7% for the DUBS.

Conclusions:

• The DUBS is the first binary laser beam shaper offering high-resolution and high-speed arbitrary beam mode generation for femtosecond lasers.
• The DUBS's capabilities position it for significant applications in nonlinear microscopy, optical manipulation, and laser-based micro/nanoscale machining.
• The technology showcases the potential of DMDs in advanced laser beam shaping applications.