Multi-wavelength photoacoustic system based on high-power diode laser bars

Overdrive Short Pulse High Peak Power Diode Lasers Without Catastrophic Optical Damage

“…The main problem of this solution is the very poor beam quality of diode laser bars and stacks, which leads to the use of complex optics to correct the beam, although recently there were advances to solve this problem [30], [31]. Another simpler but less scalable solution is to combine multiple chips with a fiber package and individual current drivers [32]. With these peak powers and pulse widths this system would improve the performance of current multi-diode lasers (bars) optoacoustic systems imaging actually with peak powers of 10 kW, pulse duration of 136 ns and energies of 1.4 mJ [33] and could also improve the range of LIDAR systems by several orders of magnitude.…”

Beam-shaping design for multi-wavelength diode laser stack system coupled into optical fiber for biomedical applications

“…In the case of diode laser bars, the usefulness of the BTS as beam shaping elements has been already reported (Leggio et al, 2017;Leggio et al, 2021). The case where multiple diode laser bars (i.e, a diode laser stack) clearly requires further optical management.…”

“…1 shows the six diode laser stacks arranged in pairs as follows: 790 nm (blue) and 808 nm (green), 940 nm (magenta) and 980 nm (cyan), 830 nm (red), and 915 nm (yellow). In addition, optical elements such as the BTS (first two elements of BTS-HOC 200-400, Limo GmbH) (Leggio et al, 2017;Leggio et al, 2021), the two reflection mirrors (PF20-03-P01, Thorlabs Inc.), and one of the dichroic mirrors (① DMLP900L, Thorlabs Inc.) have also been picked from the catalogues. However, the polarization beam combiners, the quartz-plate stacks (Figs.…”

“…The coupling scheme proposed in this work can reduce the size and production cost when compared with other schemes previously proposed (Ghasemi et al, 2011). In previous works (Leggio et al, 2017;Leggio et al, 2021), the authors included beam transformation systems (BTSs, i.e., two FAC lenses with a beam twister) to rearrange the beam of multiple diode laser bars in a multispectral scheme. Recent studies (Lin et al, 2020) proposed an innovative beam shaping technique to homogenize the beam quality of two diode laser stacks.…”

“…Like schemes of Ref. (Leggio et al, 2017;Leggio et al, 2021), in this work, we use FAC lenses and beam twisters to collimate and homogenize the astigmatic beam of the individual bars and we extend this design to a setup consisting of six diode laser stacks. Polarization beam combiners are used to split the beams of each diode laser stack in the vertical axis, and the quartz-plate stacks to rearrange each pair of adjacent wavelengths in the horizontal axis by embedding one beam into the lightless regions of the other in the vertical axis.…”