Compact fiber-delivered Cr:forsterite laser for nonlinear light microscopy

Abstract

We demonstrate a compact and self-starting fiber-delivered femtosecond Cr:forsterite laser for nonlinear light microscopy. A semiconductor saturable absorber mirror provides the self-starting mechanism and maintains long-term stability in the laser cavity. Four double-chirped mirrors are employed to reduce the size of the cavity and to compensate for group velocity dispersion. Delivered by a large-mode-area photonic crystal fiber, the generated laser pulses can be compressed down to be with a nearly transform-limited pulse width with 2.2-nJ fiber-output pulse energy. Based on this fiber-delivered Cr:forsterite laser source, a compact and reliable two-photon fluorescence microscopy system can thus be realized.

Imaging granularity of leukocytes with third harmonic generation microscopy

“…Compared with other techniques, such as μ-OCT or spectrally-encoded microscopy, technical challenges for the implementation of endoscopy include miniaturized high-NA (NA > 0.8) focusing objectives, fibers with low nonlinearity, good THG collection efficiency with the same fiber, miniaturized scanning mechanism, and a compact laser system. In our preliminary studies, we have built a compact Cr:forsterite laser system [24], miniaturized the scanning system by a micro-electro-mechanical system mirror [25,26], used a multimode fiber to reduce pulse broadening [26], and successfully obtained sufficient THG signals through the same fiber [26]. Therefore, we believe THG endoscopy for the examination of leukocytes in the human body can be realized in the near future.…”

Determination of chronological aging parameters in epidermal keratinocytes by in vivo harmonic generation microscopy

“…(c) The implementation of the vacuum-pump plate which is combined with sample stage of inverted microscope.) [16]. A 1230 nm femtosecond Cr-F laser was used for excitation to lessen skin attenuation [18–20]. Using this system, a submicron and 1 μm resolution in lateral and axial directions and a >300 μm penetrability were achieved [16,17].…”

Cr:Forsterite‐laser‐based fiber‐optic nonlinear endoscope with higher efficiencies

“…The excitation Cr:Forsterite laser (Chan et al, 2005) provided pulses with a $300 fs pulse width, a 123 MHz repetition rate, and a 530 mW average power. An optical isolator (1230-IO-5, OFR) was inserted to prevent feedback to the laser cavity.…”