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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

Simulated mid-IR outputs of the femtosecond SPOPO.The left column of (a) and (c) shows the temporal intensity while the pump duration is 80 fs. From top to bottom, the type-0 (a) and type-I (c) QPM situations were considered respectively. The right hand column of (b) and (d) shows the cases of 40 fs pump duration. Inset: The corresponding spectral intensity and phase. The pulse intensity was respectively normalized to the ones of type-I QPM design with the same pump duration.
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f7: Simulated mid-IR outputs of the femtosecond SPOPO.The left column of (a) and (c) shows the temporal intensity while the pump duration is 80 fs. From top to bottom, the type-0 (a) and type-I (c) QPM situations were considered respectively. The right hand column of (b) and (d) shows the cases of 40 fs pump duration. Inset: The corresponding spectral intensity and phase. The pulse intensity was respectively normalized to the ones of type-I QPM design with the same pump duration.

Mentions: For the shorter 40 fs pump pulses, abnormally, the conversion efficiency of type-0 QPM scheme increases steadily as the pump intensity arises. This weird phenomenon may be ascribed to the serious pulse distortion which starts at ~1.7 GW/cm2. The pulse envelope and corresponding frequency spectrum are given in Fig. 7(b), under a pump intensity of ~2.4 GW/cm2. One can clearly see that, due to the significant GVM and the shorter pulse duration, mid-IR signal pulses appeared as a severe distorted structure with two peaks. For the other cases, the frequency spectrum and pulse envelope for both types I and 0 QPM are also given, respectively, when the quantum efficiency is maximum. In comparison, nearly transform-limited clean pulses with similar temporal duration as the initial pump pulses were produced, under the same pump intensity for the proposed GVM-absent design. For a more general description, the calculated maximum conversion efficiency versus various pump duration is presented (Fig. 6(b)). All of the data was recorded before remarkable pulse distortion turns up. It shows that the efficiency gap would be more significant for the shorter pump duration. As the same of narrow-band seeding OPA discussed earlier, the proposed scheme shows a unique advantage in the ultrafast mid-IR pulses generation. The conversion efficiency can be more than doubled with nearly unlimited bandwidth when pump duration is less than 50 fs.


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

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

Simulated mid-IR outputs of the femtosecond SPOPO.The left column of (a) and (c) shows the temporal intensity while the pump duration is 80 fs. From top to bottom, the type-0 (a) and type-I (c) QPM situations were considered respectively. The right hand column of (b) and (d) shows the cases of 40 fs pump duration. Inset: The corresponding spectral intensity and phase. The pulse intensity was respectively normalized to the ones of type-I QPM design with the same pump duration.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f7: Simulated mid-IR outputs of the femtosecond SPOPO.The left column of (a) and (c) shows the temporal intensity while the pump duration is 80 fs. From top to bottom, the type-0 (a) and type-I (c) QPM situations were considered respectively. The right hand column of (b) and (d) shows the cases of 40 fs pump duration. Inset: The corresponding spectral intensity and phase. The pulse intensity was respectively normalized to the ones of type-I QPM design with the same pump duration.
Mentions: For the shorter 40 fs pump pulses, abnormally, the conversion efficiency of type-0 QPM scheme increases steadily as the pump intensity arises. This weird phenomenon may be ascribed to the serious pulse distortion which starts at ~1.7 GW/cm2. The pulse envelope and corresponding frequency spectrum are given in Fig. 7(b), under a pump intensity of ~2.4 GW/cm2. One can clearly see that, due to the significant GVM and the shorter pulse duration, mid-IR signal pulses appeared as a severe distorted structure with two peaks. For the other cases, the frequency spectrum and pulse envelope for both types I and 0 QPM are also given, respectively, when the quantum efficiency is maximum. In comparison, nearly transform-limited clean pulses with similar temporal duration as the initial pump pulses were produced, under the same pump intensity for the proposed GVM-absent design. For a more general description, the calculated maximum conversion efficiency versus various pump duration is presented (Fig. 6(b)). All of the data was recorded before remarkable pulse distortion turns up. It shows that the efficiency gap would be more significant for the shorter pump duration. As the same of narrow-band seeding OPA discussed earlier, the proposed scheme shows a unique advantage in the ultrafast mid-IR pulses generation. The conversion efficiency can be more than doubled with nearly unlimited bandwidth when pump duration is less than 50 fs.

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