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Tunable continuous wave emission via phase-matched second harmonic generation in a ZnSe microcylindrical resonator.

Vukovic N, Healy N, Sparks JR, Badding JV, Horak P, Peacock AC - Sci Rep (2015)

Bottom Line: Whispering gallery mode microresonators made from crystalline materials are of great interest for studies of low threshold nonlinear phenomena.Visible red light is observed when pumped with a telecommunications band source by a process that is phase-matched between different higher order radial modes, possible due to the good spatial overlap between the pump and signal in the small volume resonator.By exploiting the geometrical flexibility offered by the fibre platform together with the ultra-wide 500-22000 nm transmission window of the ZnSe material, we expect these resonators to find use in applications ranging from spectroscopy to quantum information systems.

View Article: PubMed Central - PubMed

Affiliation: Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK.

ABSTRACT
Whispering gallery mode microresonators made from crystalline materials are of great interest for studies of low threshold nonlinear phenomena. Compared to amorphous materials, crystalline structures often exhibit desirable properties such as high indices of refraction, high nonlinearities, and large windows of transparency, making them ideal for use in frequency comb generation, microlasing and all-optical processing. In particular, crystalline materials can also possess a non-centrosymmetric structure which gives rise to the second order nonlinearity, necessary for three photon processes such as frequency doubling and parametric down-conversion. Here we report a novel route to fabricating crystalline zinc selenide microcylindrical resonators from our semiconductor fibre platform and demonstrate their use for tunable, low power continuous wave second harmonic generation. Visible red light is observed when pumped with a telecommunications band source by a process that is phase-matched between different higher order radial modes, possible due to the good spatial overlap between the pump and signal in the small volume resonator. By exploiting the geometrical flexibility offered by the fibre platform together with the ultra-wide 500-22000 nm transmission window of the ZnSe material, we expect these resonators to find use in applications ranging from spectroscopy to quantum information systems.

No MeSH data available.


Related in: MedlinePlus

Tunable frequency conversion.Measured second harmonic emission (relative counts) for different pump wavelengths in ZnSe resonators with diameters of (a) 15 μm and (b) 20 μm.
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f4: Tunable frequency conversion.Measured second harmonic emission (relative counts) for different pump wavelengths in ZnSe resonators with diameters of (a) 15 μm and (b) 20 μm.

Mentions: To demonstrate the value of this additional degree of control over the phase-matching conditions, Fig. 4(a) shows how the second harmonic emission can be tuned over 10 nm, corresponding to 20 nm of pump tuning in Fig. 3(b). To achieve SHG over this range the coupling was optimized through a combination of adjusting the polarization to tune between the TE and TM modes, and the angle of the TFC to vary the mode height. It is clear from these spectra that although the maximum second harmonic efficiency is obtained for the original mode pair with the smallest ΔλWGM, it is nevertheless possible to phase-match several different mode pairs: λP1 = 1537 nm and λs1 = 768.3 nm, λP2 = 1544 nm and λs2 = 772 nm, λP3 = 1548.8 nm and λs3 = 774.4 nm, λP4 = 1556.4 nm and λs4 = 778.2 nm . Significantly, we believe that this is the largest tunability of harmonic generation demonstrated in a resonator of fixed size26. However, as we have fabricated ZnSe fibres with other core diameters, these provide a convenient means through which to investigate tuning the SHG even further.


Tunable continuous wave emission via phase-matched second harmonic generation in a ZnSe microcylindrical resonator.

Vukovic N, Healy N, Sparks JR, Badding JV, Horak P, Peacock AC - Sci Rep (2015)

Tunable frequency conversion.Measured second harmonic emission (relative counts) for different pump wavelengths in ZnSe resonators with diameters of (a) 15 μm and (b) 20 μm.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4488835&req=5

f4: Tunable frequency conversion.Measured second harmonic emission (relative counts) for different pump wavelengths in ZnSe resonators with diameters of (a) 15 μm and (b) 20 μm.
Mentions: To demonstrate the value of this additional degree of control over the phase-matching conditions, Fig. 4(a) shows how the second harmonic emission can be tuned over 10 nm, corresponding to 20 nm of pump tuning in Fig. 3(b). To achieve SHG over this range the coupling was optimized through a combination of adjusting the polarization to tune between the TE and TM modes, and the angle of the TFC to vary the mode height. It is clear from these spectra that although the maximum second harmonic efficiency is obtained for the original mode pair with the smallest ΔλWGM, it is nevertheless possible to phase-match several different mode pairs: λP1 = 1537 nm and λs1 = 768.3 nm, λP2 = 1544 nm and λs2 = 772 nm, λP3 = 1548.8 nm and λs3 = 774.4 nm, λP4 = 1556.4 nm and λs4 = 778.2 nm . Significantly, we believe that this is the largest tunability of harmonic generation demonstrated in a resonator of fixed size26. However, as we have fabricated ZnSe fibres with other core diameters, these provide a convenient means through which to investigate tuning the SHG even further.

Bottom Line: Whispering gallery mode microresonators made from crystalline materials are of great interest for studies of low threshold nonlinear phenomena.Visible red light is observed when pumped with a telecommunications band source by a process that is phase-matched between different higher order radial modes, possible due to the good spatial overlap between the pump and signal in the small volume resonator.By exploiting the geometrical flexibility offered by the fibre platform together with the ultra-wide 500-22000 nm transmission window of the ZnSe material, we expect these resonators to find use in applications ranging from spectroscopy to quantum information systems.

View Article: PubMed Central - PubMed

Affiliation: Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK.

ABSTRACT
Whispering gallery mode microresonators made from crystalline materials are of great interest for studies of low threshold nonlinear phenomena. Compared to amorphous materials, crystalline structures often exhibit desirable properties such as high indices of refraction, high nonlinearities, and large windows of transparency, making them ideal for use in frequency comb generation, microlasing and all-optical processing. In particular, crystalline materials can also possess a non-centrosymmetric structure which gives rise to the second order nonlinearity, necessary for three photon processes such as frequency doubling and parametric down-conversion. Here we report a novel route to fabricating crystalline zinc selenide microcylindrical resonators from our semiconductor fibre platform and demonstrate their use for tunable, low power continuous wave second harmonic generation. Visible red light is observed when pumped with a telecommunications band source by a process that is phase-matched between different higher order radial modes, possible due to the good spatial overlap between the pump and signal in the small volume resonator. By exploiting the geometrical flexibility offered by the fibre platform together with the ultra-wide 500-22000 nm transmission window of the ZnSe material, we expect these resonators to find use in applications ranging from spectroscopy to quantum information systems.

No MeSH data available.


Related in: MedlinePlus