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Group velocity mismatch-absent nonlinear frequency conversions for mid-infrared femtosecond pulses generation.

Zhong H, Zhang L, Li Y, Fan D - Sci Rep (2015)

Bottom Line: The system employs MgO-doped periodically poled LiNbO3 as the nonlinear medium.Desired group-velocity dispersion would be obtained via appropriately temperature regulation.Compared with the conventional scheme of type-0 QPM, the quantum-efficiency can be more than doubled with nearly unlimited bandwidth.

View Article: PubMed Central - PubMed

Affiliation: SZU-NUS Collaborative Innovation Center for Optoelectronic Science &Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.

ABSTRACT
A novel group velocity mismatch (GVM) absent scheme for nonlinear optical parametric procedure in mid-infrared was developed with type-I quasi phase matching by use of an off-digital nonlinear optical coefficient d31. This was achieved by matching of the group velocities of the pump and the signal waves, while the phase velocities were quasi phase matched. The system employs MgO-doped periodically poled LiNbO3 as the nonlinear medium. Desired group-velocity dispersion would be obtained via appropriately temperature regulation. To demonstrate its potential applications in ultrafast mid-infrared pulses generation, aiming at a typical mid-infrared wavelength of ~3.2 μm, design examples of two basic nonlinear frequency conversion procedures are studied for both the narrow-band seeding mid-IR optical parametric amplification (OPA) and the synchronously pumped femtosecond optical parametric oscillation (SPOPO). Compared with the conventional scheme of type-0 QPM, the quantum-efficiency can be more than doubled with nearly unlimited bandwidth. The proposed GVM- absent phase matching design may provide a promising route to efficient and broadband sub-100 fs mid-infrared ultrafast pulses generation without group-velocity walk-off.

No MeSH data available.


Related in: MedlinePlus

Schematic of the basic linear-cavity SPOPO setup.M1 is a dielectric mirror for in-coupling of the pump pulse; M2 is the out-coupler. The cavity length is matched to the repetition rate of pump laser.
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f5: Schematic of the basic linear-cavity SPOPO setup.M1 is a dielectric mirror for in-coupling of the pump pulse; M2 is the out-coupler. The cavity length is matched to the repetition rate of pump laser.

Mentions: A schematic of the basic SPOPO setup is depicted in Fig. 5. The SPOPO is designed with a basic linear cavity and singly resonant for the 3.2 μm mid-IR wavelength. A commercial Ti:sapphire femtosecond oscillator serves as the pump source, and the wavelengths of pump, signal, and idler are 0.8 μm, 3.2 μm and 1.06 μm, respectively. Through the in-coupling mirror of M1, pump pulses are coupled steered into the cavity. The nonlinear medium is a type-I QPM MgO:PPLN crystal with a poling period ∧ of ~62.8 μm. As previously discussed, because of the GVM-absent request, MgO:PPLN operates at ~175 °C in a temperature-control oven. Due to the singly resonant design, at the signal wavelength of 3.2 μm, the in-coupler is highly reflective, while the out-coupler is 80% reflective and 20% transmitted. In the meantime, M2 couples out both the residual pump and the by produced idler at 1.06 μm with high transmission in this spectral range. To achieve oscillation for the mid-IR signal wave, in addition to phase matching, the management of resonator’s dispersion is necessary. The broadband mid-IR pulses should be compressed to nearly transform-limited for each round trip. For this purpose, an additional plane-parallel plate of Ge (or ZnSe) having positive (1250 fs2/mm) GVD at 3.2 μm32 is inserted inside the cavity to compensate the negative GVD of MgO:PPLN (−760 fs2/mm).


Group velocity mismatch-absent nonlinear frequency conversions for mid-infrared femtosecond pulses generation.

Zhong H, Zhang L, Li Y, Fan D - Sci Rep (2015)

Schematic of the basic linear-cavity SPOPO setup.M1 is a dielectric mirror for in-coupling of the pump pulse; M2 is the out-coupler. The cavity length is matched to the repetition rate of pump laser.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4477408&req=5

f5: Schematic of the basic linear-cavity SPOPO setup.M1 is a dielectric mirror for in-coupling of the pump pulse; M2 is the out-coupler. The cavity length is matched to the repetition rate of pump laser.
Mentions: A schematic of the basic SPOPO setup is depicted in Fig. 5. The SPOPO is designed with a basic linear cavity and singly resonant for the 3.2 μm mid-IR wavelength. A commercial Ti:sapphire femtosecond oscillator serves as the pump source, and the wavelengths of pump, signal, and idler are 0.8 μm, 3.2 μm and 1.06 μm, respectively. Through the in-coupling mirror of M1, pump pulses are coupled steered into the cavity. The nonlinear medium is a type-I QPM MgO:PPLN crystal with a poling period ∧ of ~62.8 μm. As previously discussed, because of the GVM-absent request, MgO:PPLN operates at ~175 °C in a temperature-control oven. Due to the singly resonant design, at the signal wavelength of 3.2 μm, the in-coupler is highly reflective, while the out-coupler is 80% reflective and 20% transmitted. In the meantime, M2 couples out both the residual pump and the by produced idler at 1.06 μm with high transmission in this spectral range. To achieve oscillation for the mid-IR signal wave, in addition to phase matching, the management of resonator’s dispersion is necessary. The broadband mid-IR pulses should be compressed to nearly transform-limited for each round trip. For this purpose, an additional plane-parallel plate of Ge (or ZnSe) having positive (1250 fs2/mm) GVD at 3.2 μm32 is inserted inside the cavity to compensate the negative GVD of MgO:PPLN (−760 fs2/mm).

Bottom Line: The system employs MgO-doped periodically poled LiNbO3 as the nonlinear medium.Desired group-velocity dispersion would be obtained via appropriately temperature regulation.Compared with the conventional scheme of type-0 QPM, the quantum-efficiency can be more than doubled with nearly unlimited bandwidth.

View Article: PubMed Central - PubMed

Affiliation: SZU-NUS Collaborative Innovation Center for Optoelectronic Science &Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.

ABSTRACT
A novel group velocity mismatch (GVM) absent scheme for nonlinear optical parametric procedure in mid-infrared was developed with type-I quasi phase matching by use of an off-digital nonlinear optical coefficient d31. This was achieved by matching of the group velocities of the pump and the signal waves, while the phase velocities were quasi phase matched. The system employs MgO-doped periodically poled LiNbO3 as the nonlinear medium. Desired group-velocity dispersion would be obtained via appropriately temperature regulation. To demonstrate its potential applications in ultrafast mid-infrared pulses generation, aiming at a typical mid-infrared wavelength of ~3.2 μm, design examples of two basic nonlinear frequency conversion procedures are studied for both the narrow-band seeding mid-IR optical parametric amplification (OPA) and the synchronously pumped femtosecond optical parametric oscillation (SPOPO). Compared with the conventional scheme of type-0 QPM, the quantum-efficiency can be more than doubled with nearly unlimited bandwidth. The proposed GVM- absent phase matching design may provide a promising route to efficient and broadband sub-100 fs mid-infrared ultrafast pulses generation without group-velocity walk-off.

No MeSH data available.


Related in: MedlinePlus