Acousto-optic imaging of absorbing objects embedded in highly scattering media remains challenging since the detectable signal which is suitable for image reconstruction is weak. Yet, significant improvements were made possible by the joint use of (i) a newly developed and characterized high peak-power laser diode source and (ii) the Fourier Transform Acousto-Optic Imaging (FT-AOI) technique. Albeit FT-AOI was previously reported and demonstrated state-of-the-art performances in real-time imaging, the technique was nevertheless only remonstrated for low-scattering phantoms. Here, we highlight that using a 9 W high-peak power, while maintaining an average power below 1W, proved the ability of the overall setup to probe highly scattering media at video frame rate.
Remote sensing techniques are critical in atmospheric research, such as the monitoring of the low tropospheric temperature and the water vapor distribution. Lidar is one type of remote sensing technique that can deliver an atmospheric measurement with high spatial and temporal resolutions1. In this paper, we describe a diode-laser-based laser source at 828 nm in a master oscillator power amplifier (MOPA) architecture designed to be compatible with a water-vapor differential absorption lidar (DIAL). Two tapered amplifiers with a pulse duration of 1 μs and a repetition rate of 10 kHz are injected by a single-frequency DBR seed laser diode and coherently combined. The performance of the seed DBR laser diode and the tapered amplifiers are characterized. The phase dynamics during the pulse are analyzed, and we demonstrate that they do not significantly reduce the combining efficiency. The combined power is stabilized by a hill-climbing algorithm which actively corrects the low-frequency environmental noise. The average combined pulse energy is highly stable with relative fluctuations σon = 0.4%. The combined pulse energy reaches 10.3 μJ at the maximal operation current of 8.1 A with a combining efficiency above 82% ± 5%. This work demonstrates the coherent beam combination of micropulse tapered amplifiers and the interests of these techniques in lidar applications.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.