Table 1.

Comparison of biophotonics applications employing incoherent and coherent optical techniques.

	Biophotonics employing incoherent optical techniques	Biophotonics employing coherent optical techniques
Typical light-matter interactions	fluorescence, phosphorescence, spontaneous Raman, linear absorption, elastic scattering of incoherent light	harmonic generation, four-wave mixing, stimulated Raman, transient absorption, stimulated emission, nonlinear absorption, elastic scattering of coherent light
Complementary beneficial features	alignment-insensitive optics, widespread portable setup, low cost and low maintenance, ability to interact with large samples	high molecular specificity, high spatial resolution, intrinsic optical sectioning, capability for in vivo label-free molecular imaging without fluorescent labeling
Traditional light sources	lamp, light emitting diode, superluminescent diode, diode laser, gas laser, dye laser	mode-locked laser, pulsed laser amplifier, optical parametric amplifier or oscillator, broadband coherent source
Representative applications using fiber supercontinuum	optical sensing [12], diffuse optical tomography [13], fluorescence (lifetime) spectroscopy/imaging [14], confocal microscopy [15], optical tweezers [16], stimulated emission depletion microscopy [17]	optical coherence tomography [18], pump-probe spectroscopy and imaging [19], nonlinear optical spectroscopy and imaging [20], coherently controlled nonlinear micro-spectroscopy [21] and flow cytometry [22]