Photoacoustic microscopy using four-wave mixing in a multimode fiber

Efficient label-free in vivo photoacoustic imaging of melanoma cells using a condensed NIR-I spectral window

“…Over the last decade, nanosecond pulsed SC sources have been proposed for PA imaging [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] , [58] (see supplement Table S1 ). Some SC sources have been developed as OCT detection lasers in the combined PAM and OCT system owing to their broadband properties [49] , [55] , [56] , [58] .…”

“…However, the ultra-broadband spectrum, extending from 400 to 2400 nm, can make it difficult to achieve condensed pulse energy in a specific wavelength region of interest especially for the melanoma detection. In 2015 and 2018, Ferrari et al [52] and Buma et al [57] reported a continuum spectrum for PA imaging with a normal dispersion regime using a pump wavelength below the λ ZDW of the optical fiber. In both the output spectra, the SRS effect occurred predominantly at the beginning and continuum induced by four-wave-mixing (FWM) appeared to gradually shift toward the red-end with an increasing incident pump energy.…”

“…Ultimately, since the PA technique aims to be translated into clinical application, the research of fully integrated PAM [39] , [40] , [41] and high-speed PAM [42] , [43] , [44] , [45] , [46] , [47] have been actively progressed. Fiber-based light sources such as the supercontinuum (SC) sources [48] , [49] , [50] , [51] , [52] , [53] , [54] , [55] , [56] , [57] , [58] , [59] and stimulated Raman scattering source (SRS) sources [60] , [61] , [62] , [63] , [64] , [65] , [66] , [67] , [68] , [69] have been suggested for high-speed multispectral or functional PA imaging. The nonlinear effect can be maximized at a relatively low pump threshold power owing to the advantages of the nonlinear effective length and effective area with an optical fiber-based configuration [70] .…”

Development of a Fiber Laser with Independently Adjustable Properties for Optical Resolution Photoacoustic Microscopy

“…For the sake of enabling spectroscopic measurements, multiwavelength spectrum is obtained from a single wavelength emitting Q-switched Nd:YAG microchip laser, either through stimulated Raman scattering (SRS) or nonlinear broadening by coupling its output to a fiber36373839404142434445. For lasers utilizing SRS, major energy is distributed on a series of fixed individual wavelength peaks that result from nonlinear interaction between incoming photons through the fiber and the molecules in the fiber itself, thus offers a limited wavelength tunability46.…”

“…improved the system with a broader wavelength tuning range also with a higher repetition rate and pulse energy per band. It was also demonstrated that both discrete lines and a continuum can be produced by using four-wave mixing in a special fiber (SMF-28e)42. As a different technique, Buma et al 43.…”