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(1 - 6 of 6)
- Title
- DEVELOPMENT OF A COMPACT BROADBAND OPTICAL PARAMETRIC OSCILLATOR FOR ULTRA-SENSITIVE MOLECULAR DETECTION.
- Creator
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Crystal, Sean O, Vodopyanov, Konstantin L., University of Central Florida
- Abstract / Description
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Every gas molecule has a unique absorption spectrum that can be captured using optical spectroscopy to identify an unknown sample's composition. Frequency combs systems can provide an extremely broad mid-infrared spectrum that is very useful for molecular detection. A degenerate optical parametric oscillator (OPO) was built to generate the down-converted and shifted frequency comb spectrum. This system utilizes an ultra-short pulse 1.56�m pump laser and a never before used orientation...
Show moreEvery gas molecule has a unique absorption spectrum that can be captured using optical spectroscopy to identify an unknown sample's composition. Frequency combs systems can provide an extremely broad mid-infrared spectrum that is very useful for molecular detection. A degenerate optical parametric oscillator (OPO) was built to generate the down-converted and shifted frequency comb spectrum. This system utilizes an ultra-short pulse 1.56�m pump laser and a never before used orientation patterned gallium-phosphide crystal. Periodically polled lithium niobate (PPLN), Gallium Arsenide (GaAs) and Gallium Phosphide are all crystals used to accomplish this task. GaP, in comparison to PPLN, has (i) a larger nonlinear coefficient, (ii) much deeper infrared transparency, and (iii) smaller group dispersion � to allow for achieving broad spectral coverage. GaP also has a larger band gap than GaAs; therefore it can still be pumped with a standard telecom C-band laser. An octave-wide spanning frequency comb system was achieved and the characterization of the system is presented. This system is specifically designed to be compact and portable for initial experimental testing in the applications of medical breath analysis and combustion gas investigation.
Show less - Date Issued
- 2017
- Identifier
- CFH2000274, ucf:45837
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFH2000274
- Title
- Thermal and Waveguide Optimization of Broad Area Quantum Cascade Laser Performance.
- Creator
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Suttinger, Matthew, Lyakh, Arkadiy, Bass, Michael, Vodopyanov, Konstantin, University of Central Florida
- Abstract / Description
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Quantum Cascade Lasers are a novel source of coherent infrared light, unique in their tunability over the mid-infrared and terahertz range of frequencies. Advances in bandgap engineering and semiconductor processing techniques in recent years have led to the development of highly efficient quantum cascade lasers capable of room temperature operation. Recent work has demonstrated power scaling with broad area quantum cascade lasers by increasing active region width beyond the standard ~10 ?m....
Show moreQuantum Cascade Lasers are a novel source of coherent infrared light, unique in their tunability over the mid-infrared and terahertz range of frequencies. Advances in bandgap engineering and semiconductor processing techniques in recent years have led to the development of highly efficient quantum cascade lasers capable of room temperature operation. Recent work has demonstrated power scaling with broad area quantum cascade lasers by increasing active region width beyond the standard ~10 ?m. Taking into account thermal effects caused by driving a device with electrical power, an experimentally fitted model is developed to predict the optical power output in both pulsed and continuous operation with varying device geometry and minor changes to quantum cascade laser active region design. The effects of the characteristic temperatures of threshold current density and slope efficiency, active region geometry, and doping, on output power are studied in the model. The model is then used to refine the active region design for increased power out in continuous operation for a broad area design. Upon testing the new design, new thermal effects on rollover current density are observed. The model is then refined to reflect the new findings and more accurately predict output power characteristics.
Show less - Date Issued
- 2017
- Identifier
- CFE0007296, ucf:52174
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007296
- Title
- Broadband Mid-infrared Frequency Combs Generated via Frequency Division.
- Creator
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Ru, Qitian, Vodopyanov, Konstantin, Fathpour, Sasan, Wu, Shintson, Peale, Robert, University of Central Florida
- Abstract / Description
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Frequency combs have revolutionized metrology and demonstrated numerous applications in science and technology. Combs operating in the mid-infrared region could be beneficial for molecular spectroscopy for several reasons. First, numerous molecules have their spectroscopic signatures in this region. Furthermore, the atmospheric window (3-5(&)#181;m and 8-14(&)#181;m) is located here. Additionally, a mid-infrared frequency comb could be employed as a diagnostic tool for the many components of...
Show moreFrequency combs have revolutionized metrology and demonstrated numerous applications in science and technology. Combs operating in the mid-infrared region could be beneficial for molecular spectroscopy for several reasons. First, numerous molecules have their spectroscopic signatures in this region. Furthermore, the atmospheric window (3-5(&)#181;m and 8-14(&)#181;m) is located here. Additionally, a mid-infrared frequency comb could be employed as a diagnostic tool for the many components of human breath, as well as for detection of harmful gases and contaminants in the atmosphere. In this thesis, I used synchronously pumped subharmonic optical parametric oscillators (OPOs) operating at degeneracy to produce ultra-broadband outputs near half of the pump laser frequency. One attractive property of the subharmonic OPOs is that the signal/idler waves of the OPO are frequency- and phase-locked to the pump frequency comb. We explored three new nonlinear materials in the subharmonic OPO and demonstrated a broadband spectrum for mid-infrared frequency comb generation. (1) Orientation-patterned (OP) gallium arsenide (GaAs) was selected as the first material because it has high nonlinearity. We found that the OP-GaAs based OPO yielded an approximately two-octave wide spectrum (2.8(-)11(&)#181;m). (2) Gallium phosphide (GaP) has near zero group velocity dispersion (GVD) at 4.7 (&)#181;m and a large bandgap. The OP-GaP OPO yielded a spectrum of more than two octaves (3(-)12.5(&)#181;m). Also, because of the large bandgap, GaP is suitable for telecom 1.56-(&)#181;m pumping, having the advantage of much smaller GVD than in periodically-poled-lithium-niobite (PPLN). The telecom laser (1.56(&)#181;m) pumped OP-GaP OPO was demonstrated with more than one octave wide spectrum. (3) Finally, we explored the phenomenon of random phase matching in the zinc selenide (ZnSe) polycrystalline material. The first random phase matched OPO was demonstrated with more than one octave spectrum (3.1(-) 9(&)#181;m), which is also the first OPO based on ZnSe.
Show less - Date Issued
- 2019
- Identifier
- CFE0007718, ucf:52430
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007718
- Title
- Selective electro-magnetic absorbers based on metal-dielectric-metal thin-film cavities.
- Creator
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Nath, Janardan, Peale, Robert, Ishigami, Masa, Chernyak, Leonid, Vodopyanov, Konstantin, University of Central Florida
- Abstract / Description
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Efficient absorption of light is required for a large number of applications such as thermo-photovoltaics,thermal imaging, bio-sensing, thermal emitters, astronomy, and stealth technology. Strong light absorbers found in nature with high intrinsic losses such as carbon black, metal-black, and carbon nano-tubes etc. are bulky, not design-tunable and are hard to pattern for micro- and nano- devices. We developed thin-film, high performance absorbers in the visible, near-, mid-, long-wave - and...
Show moreEfficient absorption of light is required for a large number of applications such as thermo-photovoltaics,thermal imaging, bio-sensing, thermal emitters, astronomy, and stealth technology. Strong light absorbers found in nature with high intrinsic losses such as carbon black, metal-black, and carbon nano-tubes etc. are bulky, not design-tunable and are hard to pattern for micro- and nano- devices. We developed thin-film, high performance absorbers in the visible, near-, mid-, long-wave - and far-IR region based on a 3 layer metal-dielectric-metal (MDM) structure.We fabricated a 3-layerMDMabsorber with large band-widths in the visible and near IR spectral range without any lithographic patterning. This was the first demonstration in the optical range of the Salisbury Screen, which was originally invented for radar absorption. A Fabry-Perotcavity model depending on the thickness of the dielectric, but also the effective permittivity of the semi-transparent top metal gives calculated spectra that agree well with experiment.Secondly, we fabricated long-wave IR and far-IR MDM absorbers comprising surface patterns of periodic metal squares on the dielectric layer. Strong absorption in multiple bands were obtained, and these depended weakly on polarization and angle of incidence. Though such absorbers had been extensively studied by electrodynamic simulations and experiment in the visible to far- R regions, there existed no analytic model that could accurately predict the wavelengths of the multiple resonances. We developed a theoretical model for these absorbers based on standingwave resonances, which accurately predicts resonance wavelengths for experiment and simulation for the first time. Unlike metamaterial theories our model does not depend on the periodicity of the squares but only on their lateral dimension and the thickness of the dielectric. This feature is confirmed by synchrotron-based IR spectral imaging microscopy of single isolated squares.
Show less - Date Issued
- 2015
- Identifier
- CFE0005851, ucf:50907
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0005851
- Title
- Hybrid Integrated Photonic Platforms and Devices.
- Creator
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Chiles, Jeffrey, Fathpour, Sasan, Vodopyanov, Konstantin, Khajavikhan, Mercedeh, Chanda, Debashis, University of Central Florida
- Abstract / Description
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Integrated photonics has the potential to revolutionize optical systems by achieving drastic reductions in their size, weight and power. Remote spectroscopy, free-space communications and high-speed telecommunications are critical applications that would benefit directly from these advancements. However, many such applications require extremely wide spectral bandwidths, leading to significant challenges in their integration. The choice of integrated platform influences the optical...
Show moreIntegrated photonics has the potential to revolutionize optical systems by achieving drastic reductions in their size, weight and power. Remote spectroscopy, free-space communications and high-speed telecommunications are critical applications that would benefit directly from these advancements. However, many such applications require extremely wide spectral bandwidths, leading to significant challenges in their integration. The choice of integrated platform influences the optical transparency and functionality which can be ultimately achieved. In this work, several new platforms and technologies have been developed to meet these needs. First, the silicon-on-lithium-niobate (SiLN) platform is discussed, on which the first compact, integrated electro-optic modulator in the mid-infrared has been demonstrated. Next, results are shown in the development of the all-silicon-optical-platform (ASOP), an ultra-stable suspended membrane approach which offers broad optical transparency from 1.2 to 8.5 um and enables efficient nonlinear frequency conversion in the mid-IR. This fabrication approach is then taken further with (")anchored-membrane waveguides,(") (T-Guides) enabling single-mode and single-polarization waveguiding over a span exceeding 1.27 octaves. Afterward, a new photonic technology enabling integrated polarization beam-splitters and polarizers over unprecedented bandwidths is introduced, called topographically anisotropic photonics (TAP). Next, results on high-performance microphotonic chalcogenide glass waveguides are presented. Finally, several integrated photonics concepts suitable for further work will be discussed, such as augmentations to T-Guides and a novel technique for quasi-phase-matching.
Show less - Date Issued
- 2016
- Identifier
- CFE0006447, ucf:51408
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0006447
- Title
- Novel solid state lasers based on volume Bragg gratings.
- Creator
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Hale, Evan, Glebov, Leonid, Divliansky, Ivan, Schulzgen, Axel, Vodopyanov, Konstantin, Lyakh, Arkadiy, University of Central Florida
- Abstract / Description
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Since their invention in 1960, lasers have revolutionized modern technology, and tremendous amounts of innovation and development has gone into advancing their properties and efficiencies. This dissertation reports on further innovations by presenting novel solid state laser systems based on the volume Bragg gratings (VBGs) and the newly developed holographic phase mask (HPMs) for brightness enhancement, dual wavelength operation, and mode conversion. First, a new optical element was created...
Show moreSince their invention in 1960, lasers have revolutionized modern technology, and tremendous amounts of innovation and development has gone into advancing their properties and efficiencies. This dissertation reports on further innovations by presenting novel solid state laser systems based on the volume Bragg gratings (VBGs) and the newly developed holographic phase mask (HPMs) for brightness enhancement, dual wavelength operation, and mode conversion. First, a new optical element was created by pairing the HPM with two surface gratings creating an achromatic holographic phase mask. This new optical device successfully performed transverse mode conversion of multiple narrow line laser sources operating from 488 to 1550 nm and a broadband mode locked femtosecond source with no angular tuning. Also, two types of HPMs were tested on high power Yb fiber lasers to demonstrate high energy mode conversion.Secondly, the effects of implementing VBGs for brightness enhancement of passively Q-switched systems with large Fresnel numbers was investigated. Implementing VBGs for angular mode selection allowed for higher pulse energies to be extracted without sacrificing brightness and pulse duration. This technique could potentially be applied to construct compact cavities with 1 cm diameter beams and nearly diffraction limited beam quality.Lastly, a spectral beam combining approach was applied to create Tm3+ and Yb3+ based narrowband dual-wavelength pump sources for terahertz generation, using VBGs as frequency selectors and beam combiners. Comparison of pulse duration and synchronization was done between passive and active Q-switching operation. An experimental set up for THz generation and detection using high sensitive detectors was created, and modeling of terahertz conversion efficiencies were done
Show less - Date Issued
- 2019
- Identifier
- CFE0007812, ucf:52333
- Format
- Document (PDF)
- PURL
- http://purl.flvc.org/ucf/fd/CFE0007812
