Generation of narrow-band ultrasound with a long cavity mode-locked Nd:YAG laser

Abstract

A passively mode-locked, flashlamp-pumped Nd:YAG laser with a cavity length of 11.19 m has been developed to study the noncontact generation of narrow-band ultrasound. The individual mode-locked pulses acted as separate sources of ultrasound, producing a train of acoustic pulses with a repetition rate of about 13.4 MHz. The ultrasound was generated in an aluminum sample and remotely detected with a path stabilized Michelson interferometer. The energy in the multiple pulse acoustic signal was confined to a considerably reduced spectral range compared with that in a single pulse.

Generation of Picosecond Laser Pulses at 1064 nm from All Solid-State Passively Mode-Locked Lasers

“…The threshold of the CW Nd:YVO 4 laser was obtained at the diode pumping power of 150 mW. When the diode pumping energy is less than 540 mW, the intracavity laser energy was too low compared to the saturation fluence of the SESAM and the laser might run in CW.…”

“…The parameters of SESAM, resonator, optical element and diode laser end-pumping configurations have been researched for stable, highly efficient, passively modelocked laser operations, using commercially available components. The diode-pumped passively mode-locked solid-state Nd:YVO 4 laser generates a stable train of ultrashort laser pulses (12 ps, 8-100 MHz at 1064 nm).…”

“…By the progresses in directly diode-pumped solidstate laser material and by the appearance of a semiconductor saturable absorber mirror (SESAM) mode-lockers, compact ultrafast SESAM mode-locked all-solid laser systems have been strongly developed and dominating the ultrashort solid-state laser market for scientific, technological and medical applications [1][2][3][4]. This paper presents the results obtained in the development of CW diode-pumped ultrashort solid-state Nd:YVO 4 lasers passively modelocked with a semiconductor saturable absorber mirror (SESAM). The parameters of SESAM, resonator, optical element and diode laser end-pumping configurations have been researched for stable, highly efficient, passively modelocked laser operations, using commercially available components.…”

Multiple Cavity Laser Array Source for Laser Generation of Ultrasound

“…Among these are those requiring time modulation of the laser source [1][2][3][4][5][6]. In other words, rather than simply requiring a single pulse from the laser, a short burst of repetitive pulses is required.…”

Long Cavity Laser Excitation and Digital Filtering of Narrowband Ultrasound for Enhanced Signal-to-Noise Ratio

“…In contrast to a broadband single pulse signal, substantial bandwidth reduction has been obtained for multiple pulse signals generated with temporal modulation of a Nd:YAG laser source, either by repetitive Q switching [5] or mode locking [6]. Alternatively, various schemes for the spatial modulation of the laser source have been explored for the generation of multiple pulse 'toneburst' ultrasound.…”