Development of an IR-LED Drive Circuit for Photoacoustic Microscopy

Kanwal Ahmad, Ahmed Bashatah, Dr. Parag Chitnis, Department of Bioengineering, George Mason University 4400 University Drive, 1J7 Fairfax, VA 22030

This research seeks to investigate the viability of using infrared light-emitting diodes (IR-LEDs) as a light source for conducting optical-resolution photoacoustic microscopy (PAM). PAM is a technique that combines molecular specificity of optics with ultrasound technology. Optical microscopy is limited to shallow penetration due to strong scattering of light in tissue. In comparison, PAM can be used for deeper imaging because ultrasound scattering is an order of magnitude less than that of light. Typically, PAM uses high-intensity nanosecond lasers, but to improve portability, cost-effectiveness, and accessibility, researchers have exploring LEDs as an alternative light source. However, two major challenges in LED-based PAM persist: pulse durations that are inadequately short for time-resolved detection and low peak intensities, which result in poor signal-to-noise ratio (SNR). To alleviate this challenge, this research implements a high-speed single-LED drive-circuit developed for nanosecond pulsing to enable signal-averaging. The light from the LED is focused into an optical fiber, collimated, and then focused onto an appropriate imaging target. This acoustic response of the imaging target is detected by a high-frequency ultrasound transducer. Preliminary tests show that the circuit produces light pulses that are less than 50ns in duration and achieves a high firing rate of 1 kHz. The above-described setup is expected to produce detectable photoacoustic signals for optical resolution PAM.

Additional Abstract Information

Presenter: Kanwal Ahmad

Institution: George Mason University

Type: Poster

Subject: Electrical & Computer Engineering

Status: Approved

Time and Location

Session: Poster 6
Date/Time: Tue 2:00pm-3:00pm
Session Number: 4554