## 1 Introduction
[PERSON] then generated multicolored light (\(>\)4) with a coherent anti-Stokes Raman scattering process in several gases, and the light was used for hydrogen-fueled scramjet applications [68]. [PERSON] and [PERSON] showed that more than 13 sidebands with a spectral range from 195 nm to 2.94 \(\upmu\)m were generated in D\({}_{2}\) gas by using aRaman process [69]. In 2000, [PERSON] and his co-workers reported multicolored (\(>\)11 color) sideband generation using a cascaded highly nondegenerate FWM process in common glass [54]. Since then, studies have been conducted using other materials, such as sapphire plate [55, 56], BBO crystal [57, 58], fused silica glass [59], CaF\({}_{2}\)[60], BK7 glass [60], and diamond [61, 62]. These studies have carefully investigated the mechanism and characteristics of multicolored laser pulses. The phase-matching condition of CFWM has also been discussed and used to explain the generation of multicolored sidebands with two noncollinear pump laser pulses [60]. Our experiment has shown that more than 15 spectral upshifted sidebands and two spectral downshifted pulses can be obtained with a spectral width broader than 1.8 octaves, covering the range from UV to near-IR [55, 56, 57, 59, 60]. The spectra of the multicolored sidebands can also be tuned in the broadband spectral range by adjusting the cross-angle of the two pump beams or simply by replacing the nonlinear media [59, 60]. The pulse duration of different sidebands can be shorter than 50 fs without any extra dispersion compensation components [55, 56, 57, 59, 60], and sub-20 fs pulses can be obtained when the pump pulse chirp is carefully optimized [63]. [PERSON] and his co-workers also tried to recombine and synthesize all of the sidebands, and found that few-cycle visible-UV pulses were feasible [64, 65]. The pulse energy of the first sideband can be higher than 1 \(\upmu\)J, with an energy conversion efficiency of around 10% [66]. A low pump threshold for multicolored sideband generation was reported when materials with high nonlinear refractive indices, such as diamond [62] or nanoparticle-doped materials [70], were used as the nonlinear medium in the experiment. A compact experimental setup for multicolored laser pulse generation was also constructed [62]. Aside from the one-dimensional multicolored sidebands discussed above, a two-dimensional (2-D) multicolor sideband array can be generated when the pump intensity is increased in various materials such as a sapphire [55, 56], diamond [62], and BBO [71, 72]. Characteristically, more than 10 arrays could be generated with pump energies of several to several tens of \(\upmu\)J [55, 56, 62]. CFWM, together with beam breakup due to ellipticity of pump beams or anisotropy of nonlinear media, are thought to be the main mechanisms behind this new phenomenon [62, 71]. However, simulations based on the nonlinear Schrodinger equation are still needed for the phenomenon to be fully understood. The remainder of this paper is organized as follows. In Section 2, the theoretical analysis for multicolored pulse generation is presented. In Section 3, the characteristics of multicolored pulses are shown. The experimental setups are shown in Section 3.1. In Section 3.2, the spectral characteristics are introduced, _i.e._, the spectral range of the sidebands, the spectral width of each sideband, and the wavelength tunability of each sideband. The characterization of pulses is described in Section 3.3. Then, the pulse energy/output power and power stability are given in Section 3.4. Multicolored pulse generation with low pump threshold is discussed in Section 3.5. In Section 4, 2-D multicolored sideband arrays are introduced and discussed. Finally, conclusions and some prospects for future research directions are given in Section 5. This article is written as a summary of recent publications reported by the authors.