57 research outputs found

    Novel nonlinear frequency conversion sources in the mid-infrared

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    The goal of this thesis has been the development of a new class of advanced solid-state photonic sources for the mid-infrared (mid-IR) spectral regions, where there exists a severe shortage of practical coherent laser sources, and many scientific and technological applications can benefit. The strategy has been to exploit nonlinear optical techniques based on difference frequency generation (DFG), parametric generation and oscillation, in the latest class of mid-IR nonlinear materials, in combination with the most advanced lasers pump sources based on fiber laser technology, to realize novel, high-power coherent source with broad tunability in the mid-IR. Accordingly, we demonstrate an angle-tuned MgO:PPLN picosecond OPO, synchronously pumped by a Yb-fiber laser, for the first time to the best of our knowledge. The OPO is tunable from 1413-1900 nm in the signal togerther with idler tunability across 2418-4307 nm providing a total tunability of 2376 nm in the near-to-mid-IR region, simply by angular interrogation of the MgO:PPLN crystal at room temperature. Using a 10% output coupler, we were able to extract up to 2.4 W of signal at 1664 nm together with an idler power of 1.7 W at 2950 nm, corresponding to an overall extraction efficiency of ~45% with good beam pointing stability of better than 30 碌rad and 14 碌rad for the signal and idler, respectively. These results indicate the potential for rapid and wide tunability of high-power OPOs as compared to the temperature tuned devices. In addition, we have demonstrated a novel device based on a tandem configuration, for an injection-seeded pulsed OPO system. Using a 38-mm-long PPLN crystal, we have produced ~0.94 W of average power with 9.7% slope efficiency at 1677 nm, for a pump power of 10 W at 80 kHz repetition rate. The measured optical bandwidth of signal is less than 20 MHz, and the seeding operation is achieved over signal wavelengths ranging from 1510 to 1677 nm, providing a total seeding range of 167 nm in the near-IR region. From a more general viewpoint, the method shownhere will also work at other wavelength range of OPO as well, opening a new path towards injection-seeding or injection-locking of pulse OPOs with full tuning range and high spectral purity. Finally, we present detailed characterization of optical properties of the recently developed nonlinear material, orientation-patterned gallium phosphide (OP-GaP), by performing DFG experiments in the 2492-2782 nm wavelength range in the mid-IR. Detrimental issues such as thermal effects and residual absorption have been studied and confirmed by performing relevant measurements. Temperature and spectral acceptance bandwidths for DFG in the 40-mm-long OP-GaP crystal have been measured to be 18 潞C and 4 nm, respectively, at 1766 nm. Further, we have measured the damage threshold of the OP-GaP crystal to be 0.8 J/cm2 at 1064 nm, for the first time. The polarization dependence of the input beams on the DFG power has also been systematically investigated. To our knowledge, this is the first report on tunable DFG in OP-GaP, as well as the first nanosecond DFG source based on this new nonlinear materialEl objetivo de esta tesis era el desarrollo de una nueva clase de fuentes fot贸nicas de estado s贸lido para las regiones espectrales del infrarrojo medio (mid-IR), donde existe una gran escasez de fuentes l谩ser coherentes, que pueden ser utilizadas para muchas aplicaciones cient铆ficas y tecnol贸gicas. La estrategia consisti贸 en explotar t茅cnicas de 贸ptica no lineal basadas en la generaci贸n de frecuencias diferencia (DFG), la generaci贸n param茅trica y la oscilaci贸n 贸ptica param茅trica, usando la nuevos materiales no lineales para el mid-IR, en combinaci贸n con las fuentes de bombeo l谩ser m谩s avanzadas basadas en la tecnolog铆a l谩ser de fibra, para realizar nuevas fuentes coherentes de alta potencia y amplia sinton铆a en el mid-IR. Esta tesis presenta dispositivos de oscilaci贸n 贸ptica param茅trica (OPO) usando novedosos dise帽os, basados en materiales de quasi-phase-matching (QPM) y utilizando nuevos conceptos para facilitar la accesibilidad a la longitud de onda desde 1 渭m en la regi贸n cercana al infrarrojo cercano hasta la regi贸n del mid-IR. En consecuencia, demostramos un OPO de picosegundo con sintonizaci贸n por 谩ngulo del cristal MgO:PPLN, bombeando sincr贸nicamente por un l谩ser de fibra de Yb, por primera vez seg煤n nuestro conocimiento. El OPO es sintonizable de 1413-1900 nm en el signal juntamente con la sintonizaci贸n del idler a trav茅s de 2418-4307 nm que proporciona una sintonizaci贸n total de 2376 nm en la regi贸n del infrarojo-cercano y mid-IR, simplemente por la interrogaci贸n angular del cristal de MgO:PPLN en temperatura ambiente. Utilizando un acoplador de salida del 10%, pudimos extraer hasta 2,4 W de se帽al a 1664 nm junto con una potencia de idler de 1,7 W a 2950 nm, lo que corresponde a una eficiencia total de extracci贸n de ~45% con una buena estabilidad de apuntamiento del haz mejor que 30 渭rad y 14 渭rad para el signal y el idler, respectivamente. Estos resultados indican el potencial para una r谩pida y amplia sintonizaci贸n de OPOs de alta potencia en comparaci贸n con los dispositivos sintonizados por temperatura. Adem谩s, demostramos un novedoso dispositivo basado en una configuraci贸n en t谩ndem, para un sistema OPO pulsado con un sistema "injection-seeded". Utilizando un cristal PPLN de 38 mm de longitud, hemos producido ~0,94 W de potencia media con una eficiencia de pendiente del 9,7% a 1677 nm, para una potencia de bombeo de 10 W a una tasa de repetici贸n de 80 kHz. La anchura de banda 贸ptica de la se帽al medida es inferior a 20 MHz, y la operaci贸n de "seeding" se realiza en longitudes de onda de la se帽al que oscilan entre 1510 y 1677 nm, lo que proporciona una gama total de "seeding" de 167 nm en la regi贸n cercana al infrarrojo-cercano. Desde un punto de vista m谩s general, el m茅todo mostrado aqu铆 tambi茅n funcionar谩 en otros rangos de longitud de onda de OPO, abriendo un nuevo camino hacia el "seeding" por inyecci贸n o el bloqueo por inyecci贸n de OPOs de pulso con rango de sinton铆a completo y alta pureza espectral. Por 煤ltimo, presentamos una caracterizaci贸n detallada de las propiedades 贸pticas del material no lineal recientemente desarrollado, el orientation-patterned gallium phosphide (OP-GaP), mediante la realizaci贸n de experimentos de DFG en el rango de longitud de onda de 2492-2782 nm en el rango de infrarrojos medio. Se han estudiado y confirmado cuestiones perjudiciales como los efectos t茅rmicos y la absorci贸n residual mediante la realizaci贸n de las mediciones pertinentes. La temperatura y las anchuras de banda de aceptaci贸n espectral para DFG en el cristal OP-GaP de 40 mm de longitud han sido medidas obteniendo 18 潞C y 4 nm, respectivamente, a 1766 nm. Adem谩s, por primera vez hemos medido el umbral de da帽o del cristal OP-GaP siendo de 0,8 J/cm2 a 1064 nm. Tambi茅n se ha investigado sistem谩ticamente la dependencia de la polarizaci贸n de los haces de entrada con respecto a la potencia de la DFG. Hasta donde sabemos, este es el primer informe sobre DFG sintonizable en OP-GaP, as铆 como la primera fuente de nanosegundos DFG basada en este nuevo material no lineal

    Optical parametric generator based on orientation-patterned gallium phosphide

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    We report the first pulsed optical parametric generator based on Orientation-patterned Gallium Phosphide. The output is tunable from 1721-1850 nm (signal) and 2504-2787 nm (idler), providing a total output power of 18 mW.Peer ReviewedPostprint (author's final draft

    Singly-Resonant Optical Parametric Oscillator Based on Orientation-Patterned Gallium Phosphide

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    We report a pulsed singly-resonant optical parametric oscillator based on orientation-patterned gallium phosphide pumped by a Q-switched Nd:YAG laser. The mid-IR idler can be tuned across 2.8-3.1 渭m with an average power of 20 mW.Peer ReviewedPostprint (author's final draft

    Optical parametric generation in orientation-patterned gallium phosphide

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    We report an optical parametric generator (OPG) based on the new nonlinear material, orientation-patterned gallium phosphide (OP-GaP). Pumped by a Q-switched nanosecond Nd:YAG laser at 1064 nm with 25 kHz pulse repetition rate, the OPG can be tuned across 1721鈥1850 nm in the signal and 2504鈥2787 nm in the idler. Using a 40-mm-long crystal in single-pass configuration, we have generated a total average output power of up to 鈭18鈥夆塵W鈭18鈥夆塵W, with 鈭5鈥夆塵W鈭5鈥夆塵W of idler power at 2670 nm, for 2 W of input pump power. The OPG exhibits a passive stability in total output power better than 0.87% rms over 1 h, at a crystal temperature of 120掳C, compared to 0.14% rms for the input pump. The output signal pulses, recorded at 1769 nm, have duration of 5.9 ns for input pump pulses of 9 ns. Temperature-dependent loss measurements for the pump polarization along the [100] axis in the OP-GaP crystal have also been performed, for the first time, indicating a drop in transmission from 28.8% at 50掳C to 19.4% at 160掳C.Peer ReviewedPostprint (author's final draft

    Supercontinuum generation assisted by dispersive waves trapping in dispersion-managed integrated silicon waveguides

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    Compact chip-scale comb sources are of significant interest for many practical applications. Here, we experimentally study the generation of supercontinuum (SC) in an axially varying integrated waveguide. We show that the local tuning of the dispersion enables the continuous blue shift of dispersive waves thanks to their trapping by the strongly compressed pump pulse. This mechanism provides new insight into supercontinuum generation in a dispersion varying integrated waveguide. Pumped close to 2.2 \mum in the femtosecond regime and at a pulse energy of \sim 4 pJ, the output spectrum extends from 1.1 \mum up to 2.76 \mum and shows good coherence properties. Octave-spanning SC is also observed at input energy as low as \sim 0.9 pJ. We show that the supercontinuum is more robust against variations of the input pulse parameters and is also spectrally flatter in our numerically optimized waveguide than in fixed-width waveguides. This research demonstrates the potential of dispersion varying waveguides for coherent SC generation and paves the way for integrated low power applications, such as chip-scale frequency comb generation, precision spectroscopy, optical frequency metrology, and wide-band wavelength division multiplexing in the near-infrared

    Nanosecond difference-frequency-generation in orientation-patterned gallium phosphide

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    We report a tunable, single-pass, pulsed nanosecond difference-frequency generation (DFG) source based on the new semiconductor nonlinear material, orientation-patterned gallium phosphide (OP-GaP). The DFG source is realized by mixing the output signal of a nanosecond OPO tunable over 1723鈥1827 nm with the input pump pulses of the same OPO at 1064 nm in an OP-GaP crystal, resulting in tunable generation over 233 nm in the mid-infrared from 2548 to 2781 nm. Using a 40-mm-long crystal, we have produced 鈭14鈥夆塵W鈭14鈥夆塵W of average DFG output power at 2719 nm for a pump power of 5 W and signal power of 1 W at 80 kHz repetition rate. To the best of our knowledge, this is the first single-pass nanosecond DFG source based on OP-GaP. The DFG output beam has a TEM00TEM00 spatial mode profile and exhibits passive power stability better than 1.7% rms over 1.4 h at 2774 nm, compared to 1.6% and 0.1% rms for the signal and pump, respectively. The OP-GaP crystal is recorded to have a temperature acceptance bandwidth of 17.7掳C.Peer ReviewedPostprint (author's final draft

    Nondegenerate Two-Photon Absorption in GaAs/AlGaAs Multiple Quantum Well Waveguides

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    We present femtosecond pump-probe measurements of the nondegenerate (1960\,nm excitation and 1176--1326\,nm probe) two-photon absorption spectra of 8 \,nm GaAs/12\,nm Al0.32_{0.32}Ga0.68_{0.68}As quantum well waveguides. Experiments were performed with light pulses co-polarized normal and tangential to the quantum well plane. The results are compared to perturbative calculations of transition rates between states determined by the kp\mathbf{k}\cdot\mathbf{p} method with an 8 or 14 band basis. We find excellent agreement between theory and experiment for normal polarization, then use the model to support predictions of orders-of-magnitude enhancement of nondegenerate two-photon absorption as one constituent photon energy nears an intersubband resonance.Comment: 13 pages, 8 figure

    Performance characterization of mid-infrared difference-frequency-generation in orientation-patterned gallium phosphide

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    We present a detailed characterization of the optical properties of the recently developed nonlinear material, orientation-patterned gallium phosphide (OP-GaP), by performing difference-frequency-generation experiments in the 2548-2782 nm wavelength range in the mid-infrared (mid-IR). Temperature and spectral acceptance bandwidth measurements have been performed to study the phase-matching characteristics of OP-GaP, and the dependence of nonlinear gain on the polarization of input incident fields has been investigated. The transmission of the OP-GaP crystal at the pump and signal wavelengths has been studied and found to be dependent on polarization as well as temperature. Further, we have observed a polarization-dependent spatial shift in the transmitted pump beam through the OP-GaP sample. We have also measured the damage threshold of the OP-GaP crystal to be 0.84 J/cm2 at 1064 nm.Peer ReviewedPostprint (published version
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