2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), Jun 1, 2017
Fo r m o r e info r m a tio n, in cl u di n g o u r p olicy a n d s u b mi s sio n p r o c e d u ... more Fo r m o r e info r m a tio n, in cl u di n g o u r p olicy a n d s u b mi s sio n p r o c e d u r e , pl e a s e c o n t a c t t h e R e p o si to ry Te a m a t: u si r@ s alfo r d. a c. u k .
Journal of Nonlinear Optical Physics & Materials, 2017
An additional Section, after the Conclusions, had been mistakenly added to the original paper. Th... more An additional Section, after the Conclusions, had been mistakenly added to the original paper. This additional Section of the original paper and any associated text have now been removed. The original paper has been corrected. In the a±liation of the¯rst author, \Faculty of Advanced Technology" has been changed to \Faculty of Computing, Engineering and Science".
2008 4th International Conference on Advanced Optoelectronics and Lasers, 2008
Pattern emergence in Nature's complex systems is mostly attributed to a classic Turing instabilit... more Pattern emergence in Nature's complex systems is mostly attributed to a classic Turing instability. There, a single length-scale becomes dominant and this defines a simple emergent structure (for example, a striped or hexagonal pattern). We have investigated whether a multi-Turing instability may result in another universal type of pattern: fractals. Fractals possess proportional levels of detail across decades of length-scale, and are thus inherently scale-less. Here, we make the first predictions of spontaneous spatial fractal patterns in nonlinear ring cavities. This will include the first reported spatial optical fractals arising from purely-absorptive nonlinearity. Analyses reveal characteristic (multi-Turing) spectral features for both dispersive and absorptive cavities. Simulations verify and quantify the fractal properties of the spontaneously-patterned light. Our findings greatly widen the scope for potential realization and exploitation of fractal light sources. In Nature-inspired device and system architectures, such sources are likely to play a pivotal role in developments.
2011 11th International Conference on Laser and Fiber-Optical Networks Modeling (LFNM), 2011
Uniform and regular systems can generate optical fractals. After characterizing different fractal... more Uniform and regular systems can generate optical fractals. After characterizing different fractal-generating systems, emphasis is placed on the roles of boundary conditions and cavity feedback. New aspects of linear and nonlinear optical fractals are presented, along with considerations of system coherence and novel connections to some classic systems and configurations.
Image Processing: Machine Vision Applications IV, 2011
Being a low cost method, the ball crater method is being widely used in both the laboratory and i... more Being a low cost method, the ball crater method is being widely used in both the laboratory and industry for thickness measurements of coatings. A crucial step of this technique is the determination of the radii of the crater circles from a microscope image. The accuracy of the thickness value is mostly defined by the accuracy of radius measurements. Traditional methods of measuring the radii involve human operators, who inevitably introduce measurement uncertainty. In this work, we propose an automated method of estimating the crater radii with the aid of image processing. It measures the radius by fitting a circle to all edge points of the crater circle, which is extracted from the microscope image of the crater by using image processing techniques. It enables automating the process of determining the coating thickness from the image of a ball crater on a coating. Furthermore, because it utilizes all edge points to estimate the radius value, it increases robustness and measurement accuracy. Experimental results confirm the feasibility of our method and its potential in reducing measurement uncertainty and increasing measurement accuracy of the ball crater method.
2010 International Conference on Advanced Optoelectronics and Lasers, 2010
We present the first detailed account of kaleidoscope laser modes where the equivalent Fresnel nu... more We present the first detailed account of kaleidoscope laser modes where the equivalent Fresnel number Neq and magnification M may assume arbitrary values. Properties of these linear fractal eigenmodes are explored through extensive numerical computations. Considerations are extended to demonstration and analyses of new contexts for spontaneous nonlinear optical fractals.
A low Etendue (6.1 mm 2) yellow-green solid-state light source with optical conversion efficiency... more A low Etendue (6.1 mm 2) yellow-green solid-state light source with optical conversion efficiency up to 101.3 lumen/Watt is demonstrated by through high power laser diode pumping of a static LuAG:Ce transparent ceramic plate. A 443 nm blue laser diode array with a full-width-half-maximum (FWHM) of <1.5 nm and maximum output power of 15.2 W is used to attain a high spectral absorption efficiency. The output from the high power laser diode array is collimated, shaped, despeckled and focused to display a Gaussian-like profile with a 1.5 mm beam waist (1/e 2 radius) to stimulate a 1.2 mm thick LuAG:Ce transparent ceramic plate with an emission FWHM spectra at 505-585 nm. No thermal quenching, pump absorption saturation and obvious luminous flux decrease is found during test.
Development of a novel, cost-effective, and highly efficient mid-infrared light source has been i... more Development of a novel, cost-effective, and highly efficient mid-infrared light source has been identified as a major scientific and technological goal within the area of optical gas sensing. We have proposed and investigated a mid-infrared metamaterial thermal emitter based on micro-structured chromium thin film. The results demonstrate that the proposed thermal light source supports broadband and wide angular absorption of both TE- and TM-polarized light, giving rise to broadband thermal radiation with averaged emissivity of ∼0.94 in a mid-infrared atmospheric window of 8-14 μm. The proposed microphotonic concept provides a promising alternative mid-infrared source and paves the way towards novel optical gas sensing platforms for many applications.
Solid State Lasers XXI: Technology and Devices, 2012
ABSTRACT A mode hop free tunable blue laser at 465 nm based on an external cavity system is inves... more ABSTRACT A mode hop free tunable blue laser at 465 nm based on an external cavity system is investigated. The single longitudinal mode second-harmonic generation (SHG) blue laser was generated using quasi-phase matching (QPM) based MgO: PPLN pumped by infrared diode laser at 930 nm with one lasing longitudinal mode. The wide turning rang in excess of 100 GHz is achieved by using combination the etalon, silica glass plate and narrow band filter into the external cavity, which only allow one longitudinal mode running and operating wavelength tuning. 30 mw blue light was obtained at wavelength of 465 nm with beam quality better then M2 =1.3.
We present a brief account of some recent theoretical advances made within the Institute for Mate... more We present a brief account of some recent theoretical advances made within the Institute for Materials Research in the field of broadband non-linear optics. Particular contexts include: angular aspects of non-linear beam propagation and interactions (Helmholtz soliton theory); the theory of spontaneous spatial optical fractals in non-linear systems; and a profoundly new regime of ultra-broadband multi-frequency Raman generation (that promises spontaneous attosecond pulse trains).
We report on an existence of a highly lossy interface mode (HLIM) in a designed plasmonic nanostr... more We report on an existence of a highly lossy interface mode (HLIM) in a designed plasmonic nanostructure for perfect absorption of the incident optical waves. Interactions between the single thinmetallic-layer (T M L) and slits arrays for excitation of the HLIM in the proposed plasmonic absorber are investigated, and eigenfrequency formula for the HLIM is derived. Analytical and numerical results show that the HLIM is frequency-selective, opens a narrow and steep absorption band in photonic stopband of the slits arrays. Due to the HLIM lossy characteristic, surface plasmon polaritons are significantly trapped at the T M L interface with absorption close to 100%.
2012 Symposium on Photonics and Optoelectronics, 2012
ABSTRACT Based on a two-dimensional plasmonic metal-dielectric-metal waveguide with a thin metall... more ABSTRACT Based on a two-dimensional plasmonic metal-dielectric-metal waveguide with a thin metallic layer and dual nanocavites inserted in the core, a novel nanostructured absorber is presented. A transfer matrix model for the proposed structure is established, and the optical spectra are investigated. Design results show that a narrow reflection spectrum occurs at position of the near-unity absorption, and is significantly influenced by the environment. It is able to generate a sensitivity as high as 1000 nm/RIU, which be used as an excellent sensing platform for chemical and biochemically relevant molecules.
ABSTRACT The ability to actively control light has long been a major scientific and technological... more ABSTRACT The ability to actively control light has long been a major scientific and technological goal. We proposed a scheme that allows for active control of light by utilizing the nonreciprocal magnetoplasmonic effect. As a proof of concept, we applied current signal through an ultrathin metallic film in a magneto-plasmonic multilayer and found that dynamic photonic nonreciprocity appears in magnetic-optical material layer due to the magnetic field being induced from current signal and modulates surface plasmon polaritons trapped in the metal surface and the light reflected. The proposed concept provides a possible way for the active control of light and could find potential applications such as ultrafast optoelectronic signal processing for plasmonic nanocircuit technology and ultrafast/large-aperture free-space electro-optic modulation platform for wireless laser communication technology.
A method of reducing the uncertainty in measuring coating thickness using the ball crater method ... more A method of reducing the uncertainty in measuring coating thickness using the ball crater method is proposed in this research. A crucial step of the ball crater method is measurement of the radii of the crater circles from a microscope image. While traditional methods of measuring the radii involve human operators, who inevitably introduce measurement uncertainty, the proposed approach measures a radius by fitting a circle (or an ellipse) to all edge points of a crater circle edge, which is extracted from the microscope image of the crater by using image processing techniques. This eliminates the subjectiveness introduced by human operators and reduces the measurement uncertainty. Experimental results confirm the feasibility of our method and its potential in reducing measurement uncertainty and increasing measurement accuracy of the ball crater method. The use of all edge points in the estimation of the radius in the proposed method also enables accurate determination of coating thickness from an image of a crater taken from a direction other than the normal to the coating surface.
By using the calculation theory of the phase-matching direction and e ective nonlinear coe cient ... more By using the calculation theory of the phase-matching direction and e ective nonlinear coe cient of frequency doubling in biaxial crystal, we calculate the e ective nonlinear coe cients at di erent frequency-doubling phase-matching directions of the three main uorescent lines (936, 1060, 1331 nm) of Nd:GdCOB crystal. The space distribution curves of e ective nonlinear coe cient are drawn. Two crystal specimens are cut at the optimal type I phase matching angles: for specimen 1, Â = 65 • , = 34:6 • (the ÿrst octant); for specimen 2, Â = 66:5 • , = 145:5 • (the second octant). When pumped by Datachroom-5000 pulsed dye laser, the output self-frequency-doubling red laser in specimen 2 is 0:62 mJ, and the corresponding conversion e ciency is 2.5%. Under the same pumping condition, the output red laser of specimen 1 is much smaller than that of specimen 2, which is well in agreement with the theoretical calculation.
2017 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC), Jun 1, 2017
Fo r m o r e info r m a tio n, in cl u di n g o u r p olicy a n d s u b mi s sio n p r o c e d u ... more Fo r m o r e info r m a tio n, in cl u di n g o u r p olicy a n d s u b mi s sio n p r o c e d u r e , pl e a s e c o n t a c t t h e R e p o si to ry Te a m a t: u si r@ s alfo r d. a c. u k .
Journal of Nonlinear Optical Physics & Materials, 2017
An additional Section, after the Conclusions, had been mistakenly added to the original paper. Th... more An additional Section, after the Conclusions, had been mistakenly added to the original paper. This additional Section of the original paper and any associated text have now been removed. The original paper has been corrected. In the a±liation of the¯rst author, \Faculty of Advanced Technology" has been changed to \Faculty of Computing, Engineering and Science".
2008 4th International Conference on Advanced Optoelectronics and Lasers, 2008
Pattern emergence in Nature's complex systems is mostly attributed to a classic Turing instabilit... more Pattern emergence in Nature's complex systems is mostly attributed to a classic Turing instability. There, a single length-scale becomes dominant and this defines a simple emergent structure (for example, a striped or hexagonal pattern). We have investigated whether a multi-Turing instability may result in another universal type of pattern: fractals. Fractals possess proportional levels of detail across decades of length-scale, and are thus inherently scale-less. Here, we make the first predictions of spontaneous spatial fractal patterns in nonlinear ring cavities. This will include the first reported spatial optical fractals arising from purely-absorptive nonlinearity. Analyses reveal characteristic (multi-Turing) spectral features for both dispersive and absorptive cavities. Simulations verify and quantify the fractal properties of the spontaneously-patterned light. Our findings greatly widen the scope for potential realization and exploitation of fractal light sources. In Nature-inspired device and system architectures, such sources are likely to play a pivotal role in developments.
2011 11th International Conference on Laser and Fiber-Optical Networks Modeling (LFNM), 2011
Uniform and regular systems can generate optical fractals. After characterizing different fractal... more Uniform and regular systems can generate optical fractals. After characterizing different fractal-generating systems, emphasis is placed on the roles of boundary conditions and cavity feedback. New aspects of linear and nonlinear optical fractals are presented, along with considerations of system coherence and novel connections to some classic systems and configurations.
Image Processing: Machine Vision Applications IV, 2011
Being a low cost method, the ball crater method is being widely used in both the laboratory and i... more Being a low cost method, the ball crater method is being widely used in both the laboratory and industry for thickness measurements of coatings. A crucial step of this technique is the determination of the radii of the crater circles from a microscope image. The accuracy of the thickness value is mostly defined by the accuracy of radius measurements. Traditional methods of measuring the radii involve human operators, who inevitably introduce measurement uncertainty. In this work, we propose an automated method of estimating the crater radii with the aid of image processing. It measures the radius by fitting a circle to all edge points of the crater circle, which is extracted from the microscope image of the crater by using image processing techniques. It enables automating the process of determining the coating thickness from the image of a ball crater on a coating. Furthermore, because it utilizes all edge points to estimate the radius value, it increases robustness and measurement accuracy. Experimental results confirm the feasibility of our method and its potential in reducing measurement uncertainty and increasing measurement accuracy of the ball crater method.
2010 International Conference on Advanced Optoelectronics and Lasers, 2010
We present the first detailed account of kaleidoscope laser modes where the equivalent Fresnel nu... more We present the first detailed account of kaleidoscope laser modes where the equivalent Fresnel number Neq and magnification M may assume arbitrary values. Properties of these linear fractal eigenmodes are explored through extensive numerical computations. Considerations are extended to demonstration and analyses of new contexts for spontaneous nonlinear optical fractals.
A low Etendue (6.1 mm 2) yellow-green solid-state light source with optical conversion efficiency... more A low Etendue (6.1 mm 2) yellow-green solid-state light source with optical conversion efficiency up to 101.3 lumen/Watt is demonstrated by through high power laser diode pumping of a static LuAG:Ce transparent ceramic plate. A 443 nm blue laser diode array with a full-width-half-maximum (FWHM) of <1.5 nm and maximum output power of 15.2 W is used to attain a high spectral absorption efficiency. The output from the high power laser diode array is collimated, shaped, despeckled and focused to display a Gaussian-like profile with a 1.5 mm beam waist (1/e 2 radius) to stimulate a 1.2 mm thick LuAG:Ce transparent ceramic plate with an emission FWHM spectra at 505-585 nm. No thermal quenching, pump absorption saturation and obvious luminous flux decrease is found during test.
Development of a novel, cost-effective, and highly efficient mid-infrared light source has been i... more Development of a novel, cost-effective, and highly efficient mid-infrared light source has been identified as a major scientific and technological goal within the area of optical gas sensing. We have proposed and investigated a mid-infrared metamaterial thermal emitter based on micro-structured chromium thin film. The results demonstrate that the proposed thermal light source supports broadband and wide angular absorption of both TE- and TM-polarized light, giving rise to broadband thermal radiation with averaged emissivity of ∼0.94 in a mid-infrared atmospheric window of 8-14 μm. The proposed microphotonic concept provides a promising alternative mid-infrared source and paves the way towards novel optical gas sensing platforms for many applications.
Solid State Lasers XXI: Technology and Devices, 2012
ABSTRACT A mode hop free tunable blue laser at 465 nm based on an external cavity system is inves... more ABSTRACT A mode hop free tunable blue laser at 465 nm based on an external cavity system is investigated. The single longitudinal mode second-harmonic generation (SHG) blue laser was generated using quasi-phase matching (QPM) based MgO: PPLN pumped by infrared diode laser at 930 nm with one lasing longitudinal mode. The wide turning rang in excess of 100 GHz is achieved by using combination the etalon, silica glass plate and narrow band filter into the external cavity, which only allow one longitudinal mode running and operating wavelength tuning. 30 mw blue light was obtained at wavelength of 465 nm with beam quality better then M2 =1.3.
We present a brief account of some recent theoretical advances made within the Institute for Mate... more We present a brief account of some recent theoretical advances made within the Institute for Materials Research in the field of broadband non-linear optics. Particular contexts include: angular aspects of non-linear beam propagation and interactions (Helmholtz soliton theory); the theory of spontaneous spatial optical fractals in non-linear systems; and a profoundly new regime of ultra-broadband multi-frequency Raman generation (that promises spontaneous attosecond pulse trains).
We report on an existence of a highly lossy interface mode (HLIM) in a designed plasmonic nanostr... more We report on an existence of a highly lossy interface mode (HLIM) in a designed plasmonic nanostructure for perfect absorption of the incident optical waves. Interactions between the single thinmetallic-layer (T M L) and slits arrays for excitation of the HLIM in the proposed plasmonic absorber are investigated, and eigenfrequency formula for the HLIM is derived. Analytical and numerical results show that the HLIM is frequency-selective, opens a narrow and steep absorption band in photonic stopband of the slits arrays. Due to the HLIM lossy characteristic, surface plasmon polaritons are significantly trapped at the T M L interface with absorption close to 100%.
2012 Symposium on Photonics and Optoelectronics, 2012
ABSTRACT Based on a two-dimensional plasmonic metal-dielectric-metal waveguide with a thin metall... more ABSTRACT Based on a two-dimensional plasmonic metal-dielectric-metal waveguide with a thin metallic layer and dual nanocavites inserted in the core, a novel nanostructured absorber is presented. A transfer matrix model for the proposed structure is established, and the optical spectra are investigated. Design results show that a narrow reflection spectrum occurs at position of the near-unity absorption, and is significantly influenced by the environment. It is able to generate a sensitivity as high as 1000 nm/RIU, which be used as an excellent sensing platform for chemical and biochemically relevant molecules.
ABSTRACT The ability to actively control light has long been a major scientific and technological... more ABSTRACT The ability to actively control light has long been a major scientific and technological goal. We proposed a scheme that allows for active control of light by utilizing the nonreciprocal magnetoplasmonic effect. As a proof of concept, we applied current signal through an ultrathin metallic film in a magneto-plasmonic multilayer and found that dynamic photonic nonreciprocity appears in magnetic-optical material layer due to the magnetic field being induced from current signal and modulates surface plasmon polaritons trapped in the metal surface and the light reflected. The proposed concept provides a possible way for the active control of light and could find potential applications such as ultrafast optoelectronic signal processing for plasmonic nanocircuit technology and ultrafast/large-aperture free-space electro-optic modulation platform for wireless laser communication technology.
A method of reducing the uncertainty in measuring coating thickness using the ball crater method ... more A method of reducing the uncertainty in measuring coating thickness using the ball crater method is proposed in this research. A crucial step of the ball crater method is measurement of the radii of the crater circles from a microscope image. While traditional methods of measuring the radii involve human operators, who inevitably introduce measurement uncertainty, the proposed approach measures a radius by fitting a circle (or an ellipse) to all edge points of a crater circle edge, which is extracted from the microscope image of the crater by using image processing techniques. This eliminates the subjectiveness introduced by human operators and reduces the measurement uncertainty. Experimental results confirm the feasibility of our method and its potential in reducing measurement uncertainty and increasing measurement accuracy of the ball crater method. The use of all edge points in the estimation of the radius in the proposed method also enables accurate determination of coating thickness from an image of a crater taken from a direction other than the normal to the coating surface.
By using the calculation theory of the phase-matching direction and e ective nonlinear coe cient ... more By using the calculation theory of the phase-matching direction and e ective nonlinear coe cient of frequency doubling in biaxial crystal, we calculate the e ective nonlinear coe cients at di erent frequency-doubling phase-matching directions of the three main uorescent lines (936, 1060, 1331 nm) of Nd:GdCOB crystal. The space distribution curves of e ective nonlinear coe cient are drawn. Two crystal specimens are cut at the optimal type I phase matching angles: for specimen 1, Â = 65 • , = 34:6 • (the ÿrst octant); for specimen 2, Â = 66:5 • , = 145:5 • (the second octant). When pumped by Datachroom-5000 pulsed dye laser, the output self-frequency-doubling red laser in specimen 2 is 0:62 mJ, and the corresponding conversion e ciency is 2.5%. Under the same pumping condition, the output red laser of specimen 1 is much smaller than that of specimen 2, which is well in agreement with the theoretical calculation.
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Papers by Jungang Huang