Air‐core fiber or photonic‐crystal rod, which is more suitable for energetic femtosecond pulse generation and three‐photon microscopy at the 1700‐nm window?

Abstract

Energetic femtosecond pulses at the 1700‐nm window are a prerequisite for deep‐tissue three‐photon microscopy (3PM). Soliton self‐frequency shift (SSFS) in photonic‐crystal (PC) rod has been the only technique to generate such pulses suitable for 3PM. Here we demonstrate through SSFS in an air‐core fiber, we can generate most energetic femtosecond soliton pulses at the 1700‐nm window, 5.2 times higher than that from PC rod. However, the air‐core soliton pulse width is 5.9 times longer than that of PC rod soliton. Based on comparative 3PM excited with both air‐core and PC rod solitons, we propose the more suitable source for 3PM. We further elucidate the challenge of generating shorter soliton pulses from air‐core fibers through numerical simulation.

High-power Raman soliton generation tunable from 1.76 to 1.84 µm in all-fiber polarization-maintaining erbium-doped amplifier

“…The other popular technique to obtain ultrashort pulses at 1700 nm excitation window is Raman soliton lasers taking advantage of the soliton self-frequency shift (SSFS) [10][11][12][13][14][15][16][17][18]. The soliton pulses propagating in optical fibers are affected by stimulated Raman scattering (SRS), causing energy to continuously transfer from the shorter wavelength to the longer wavelength, resulting in the SSFS.…”

High-Power Raman Soliton Generation at 1.7 μm in All-Fiber Polarization-Maintaining Erbium-Doped Amplifier

“…In fact, the current method to obtain the 1.7 µm high-power femtosecond fiber laser using for MPM is through SSFS in largemode-area (LMA) passive fiber. [10][11][12][13] However, the connection between the LMA passive fiber and pump sources in the laser system is achieved through spatial docking, which requires regular optical path adjustment and dust removal maintenance, resulting in low long-term stability and poor environmental adaptability of the laser system. To improving the robust and integration of system, the entirely fiberized high-power ultrashort pulse lasers without spatial structure modules have become an important research focus.…”

“…The other popular technique to obtain ultrashort pulses at 1.7 µm is Raman soliton lasers taking advantage of the soliton self-frequency shift (SSFS). [10][11][12][13][14][15][16][17][18][19] When propagating in optical fibers, soliton pulses are affected by stimulated Raman scattering (SRS), causing energy to continuously transfer from the shorter wavelength to the longer wavelength, resulting in SSFS. In fact, the current method to obtain the 1.7 µm high-power femtosecond fiber laser using for MPM is through SSFS in largemode-area (LMA) passive fiber.…”