Dynamic performance of microelectromechanical systems deformable mirrors for use in an active/adaptive two-photon...

Area of Science:

• Optics and Photonics
• Microscopy Technology
• Biomedical Engineering

Background:

• Active optics, such as deformable mirrors (DM), are crucial for controlling focal depth and aberrations in scanning laser microscopy.
• Dynamic control enables imaging of oblique surfaces and optimization of image quality across the field of view.

Purpose of the Study:

• To characterize the speed and dynamic precision of specific deformable mirrors for active and adaptive two-photon microscopy.
• To assess the suitability of Boston Micromachines Corporation Multi-DM and Revibro Optics mirrors for intrascan aberration correction and focal depth adjustment.

Main Methods:

• Performance testing of a 140-element Multi-DM mirror using step response and sinusoidal frequency sweeps for various Zernike modes.
• Testing of a 4-zone focus control mirror using step response for defocus and spherical aberration.
• Measurement of wavefront error settling times and 3 dB frequencies.

Main Results:

• The Multi-DM mirror exhibited wavefront error settling times under 52 µs for large amplitude steps and 3 dB frequencies between 6.5–10 kHz.
• The Revibro Optics mirror showed settling times under 80 µs for defocus and under 45 µs for spherical aberration.
• Achieved response speeds are adequate for intrascan correction in two-photon microscopy.

Conclusions:

• The characterized deformable mirrors possess sufficient speed and precision for real-time aberration correction and focal depth control in two-photon microscopy.
• These active optics components can enhance imaging capabilities, particularly for challenging samples and oblique surfaces.