Transducer-matched multipulse excitation for signal-to-noise ratio improvement in diode laser-based photoacoustic systems

Abstract

We analyze transducer-matched multipulse excitation as a method for improving of the signal-tonoise ratio (SNR) for diode laser-based photoacoustic systems. We discuss the principle of the technique, its advantages, and potential drawbacks and perform measurements to analyze the obtainable SNR increase. We show in experiment and computationally that a lower boundary estimate of 1.2 to 1.8 fold SNR improvement can be provided using transducer-matched pulse bursts, depending on the transducer and particular arrangement. Finally, we analyze implications that the transducer resonance effects may have on the recently introduced advanced photoacoustic techniques. The findings are of immediate interest to modalities utilizing dense pulse sequences and systems possessing limited pulse energy. In particular, transducer-matched multipulse excitation may be beneficial for diode-based photoacoustic systems operated with transducers in the range of 1 to 5 MHz since the required hardware is readily available.

Compact Laser Driver for Ultrasonic Arbitrary Position and Width Pulse Sequences Generation

“…There have been previous attempts to use spread spectrum excitation using mid-power (100 W) pulsed laser [64], but researchers had to use emulation, due to the unavailability of a fast, high current laser driver for generating pulse sequences. The acoustic response to a single pulse was measured and then pulse sequences were produced artificially, emulating spread spectrum sequence excitation.…”