Intracavity optical parametric oscillator: study of the dynamics in pulsed regime

By using a doubly passively Q-switched Nd:Gd 3 Ga 5 O 12 (Nd:GGG) laser with Cr 4? :YAG and GaAs as saturable absorbers as pump laser, simultaneous intracavity optical parametric oscillation and stimulated Raman scattering based on a single X-cut KTiOPO 4 (KTP) crystal have been realized. Under an incident diode pump power of 10.5 W, the output powers at the signal wave near 1,569 nm and the first Stokes emission near 1,094 nm were 218 and 72 mW, corresponding to the optical-to-optical conversion efficiencies of 2.08 and 0.69 %, respectively. The measured shortest pulse duration at the signal wave near 1,569 nm was 580 ps, generating a pulse peak power of 43.7 kW, while the minimum pulse duration at the first Stokes emission near 1,094 nm was 1.61 ns. By adjusting the tilt angle of the KTP crystal, up to the third Stokes scattering was also obtained.

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“…The correlation dynamics between the fundamental wave and the signal wave was given in detail in Ref. [22].…”

Section: Resultsmentioning

confidence: 99%

Simultaneous intracavity optical parametric oscillation and stimulated Raman scattering pumped by a doubly passively Q-switched Nd:GGG laser

Chu

Zhao

et al. 2014

Appl. Phys. B

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“…This bulk absorption greatly increases the optical damage threshold of the eye. Three types of eye−safe lasers are of the practical importance, i.e., lasers with er− bium (Er) doped media directly operating at 1.54 µm wave− length [1][2][3][4][5][6], Raman lasers pumped by pulsed neodymium (Nd) lasers operating at the strongest 1064 nm or 1340 nm lines [7][8][9][10], and optical parametric oscillators (OPO) pum− ped by high peak power Nd lasers [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”

Section: Introductionmentioning

confidence: 99%

Intracavity optical parametric oscillator pumped by passively Q-switched Nd:YLF laser

Żendzian

Jabczyński

Kwiatkowski

2009

Opto-Electronics Review

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We report on a passively Q-switched end pumped Nd:YLF laser including a noncritically phase-matched KTP singly resonant intracavity optical parametric oscillator (IOPO-KTP). For the Q-switching operation we have used Cr:YAG saturable absorber. The optimized passively Q-switched Nd:YLF laser without IOPO generated linearly polarized pulses of 11.5 ns and 1.07 mJ at 1047 nm. The conversion efficiency of the optimized Q-switched pulse energy at 1047 nm to 1547 nm of a signal approached about 47%. For optimizing both Nd:YLF laser and IOPO we have numerically solved a theoretical model. We have achieved 1.6-ns duration pulses at 1547 nm with energy of 0.5 mJ and peak power of above 300 kW. The beam quality was excellent (M2 ≈1).

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“…As we know [15], the basic idea of an intracavity OPO involves the use of high radiation intensities in a closed pump laser cavity, which makes it possible to achieve the OPO lasing threshold with lower (compared with an extracavity OPO) levels of pumping for the laser medium. The properties of intracavity OPOs have been studied so far mainly under conditions when the OPO has a planar cavity [16,17]. As the active medium for the pump laser, we selected a potassium gadolinium tungstate crystal, activated by neodymium ions (KGd(WO 4 ) 2 :Nd 3+ (Nd:KGW)).…”

mentioning

confidence: 99%

Eye-safe radiation source based on an optical parametric oscillator

et al. 2006

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We have studied an optical parametric oscillator (OPO) with an unstable telescopic cavity, placed inside the cavity of an actively Q-switched multimode Nd 3+ :KGW pump laser. We used a KTP crystal as the nonlinear medium for the OPO. We have compared the emission characteristics of OPOs with unstable telescopic and planar cavities. We have established that compared with the planar cavity, the unstable cavity reduces the OPO beam divergence and improves the spatial distribution of the radiation energy in the far wave zone.Based on our investigations, we have designed a compact eye-safe (λ = 1.578 µm) laser source with natural cooling, emitting (for electrical pumping energy 7.3 J) pulses with pulse energy 22 mJ and pulse duration 6 nsec. The FWHM beam divergence for the source is no greater than 3.5 mrad.Introduction. One of the most effective methods for generating eye-safe radiation is based on an optical parametric oscillator using crystals in the KTP family, pumped by radiation from Nd 3+ -containing lasers. KTP and KTA crystals have high radiation resistance, high nonlinear optical coefficients, and ensure lasing under noncritical phase matching conditions. Because of the indicated properties, they make it possible to rather efficiently, using single-cavity OPOs, to convert the wavelength of emission from Nd lasers to the wavelength range 1.54-1.61 µm. Single-cavity OPOs based on crystals of the KTP family are constructed using Nd:YAG, Nd:YLiF, and Nd:YVO 4 lasers with lamp and diode pumping [1][2][3][4].With pumping by Q-switched Nd lasers, OPOs based on KTP crystals can generate nanosecond pulses with energies of tens and hundreds of millijoules [5-10]. Such good power characteristics make KTP OPOs promising for many practical applications. However, the OPO beam divergence and field structure are no less important characteristics of eye-safe radiation (for example, for detection and ranging). Previously, high-power OPOs were generally constructed using linear planar cavities which, when the pump beam is matched with an eigenmode of the OPO cavity, ensure a sufficiently large waist (a few millimeters) and thus make it possible to operate below the damage threshold of the crystals. However, the divergence of the radiation from an OPO with a planar cavity is relatively large, since for short cavities it is determined more by the geometric aperture of the pumped volume than by the pump beam quality, if the pump beam divergence exceeds the diffraction limit [11]. A decrease in the divergence of the OPO radiation is facilitated by use of a ring cavity [10]. However, in order to achieve high radiation energy, this approach requires using several KTP crystals in the OPO, which increases the cost of the source.As shown by recent theoretical [12] and experimental [13,14] investigations, the divergence of the OPO radiation can be reduced by using an unstable telescopic cavity. The advantage of such a cavity over a planar cavity has been demonstrated for extracavity OPOs, pumped by laser beams with divergence close to...

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Intracavity optical parametric oscillator: study of the dynamics in pulsed regime

Cited by 110 publications

References 6 publications

Simultaneous intracavity optical parametric oscillation and stimulated Raman scattering pumped by a doubly passively Q-switched Nd:GGG laser

Simultaneous intracavity optical parametric oscillation and stimulated Raman scattering pumped by a doubly passively Q-switched Nd:GGG laser

Intracavity optical parametric oscillator pumped by passively Q-switched Nd:YLF laser

Eye-safe radiation source based on an optical parametric oscillator

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