LASER LINE TUNABLE FILTER

ABSTRACT

N. Akopian¹, U. Perinetti¹, L. Wang^2,3, A. Rastelli², O. G. Schmidt², and V. Zwiller¹
1. Quantum Transport, Kavli Institute of Nanoscience, TU Delft, 2628CJ Delft, The Netherlands
2. Max Planck Institute for Solid State Research, Heisenbergstr. 1, D-70569 Stuttgart, Germany
3. Institute for Integrative Nanosciences, IFW Dresden, Helmholtzstr. 20, 01069 Dresden, Germany  

We study single GaAs quantum dots with optical transitions that can be brought into resonance with the widely used D₂ transitions of rubidium atoms. We achieve resonance by Zeeman or Stark shifting the quantum dot levels. We discuss an energy stabilization scheme based on the absorption of quantum dot photoluminescence in a rubidium vapor. This offers a scalable means to counteract slow spectral diffusion in quantum dots.

1 T. R. Zaman, X. Guo and R. J. Ram, 

Magneto-optical (MO) effects are used either as tools for probing the magnetization reversal characteristics of a wide range of sample types, or as an effective way to modify the polarization of light via induced magnetization state in samples. In transparent samples, the Faraday effect (rotation of the polarization of light proportional to the magnetic induction field and optical path in the medium) can be used to elaborate Faraday rotators, a key element in the design of optical isolators (1). Along with other MO effects such as Kerr measurements, they provide a non-destructive probe for in-situ measurements of samples, such as thin films.

Debashri Ghosh, Samudra Roy, Mrinmay Pal, Philippe Leproux, Pierre Viale, Vincent Tombelaine, and Shyamal K. Bhadra

ABSTRACT

We report experimentally observed extreme blue-enhanced supercontinuum (SC) generation down to 372 nm wavelength in simply designed and easily fabricated nonlinear microstructured optical fibers (MOFs). Three different MOFs of various core sizes and dispersion profiles are fabricated in order to optimize the parameters for achieving deeper blue components by group-index matching. The physical mechanism involved in the generation of extreme blue component is explained along with other nonlinear processes participating in the spectral broadening. We also explore the extent of applicability of the group-index matching technique for obtaining blue-enhanced SC and finally optimize the location of the zero dispersion wavelength (ZDW) with respect to the pump wavelength to achieve the maximum blue shift.

© 2011 IEEE

Rahul Yadav, Kye-Sung Lee, Jannick P. Rolland, James M. Zavislan, James V. Aquavella, and Geunyoung Yoon

ABSTRACT

An optical coherence tomography (OCT) for high axial resolution corneal imaging is presented. The system uses 375 nm bandwidth (625 to 1000 nm) from a broadband supercontinuum light source. The system was developed in free space to minimize image quality degradation due to dispersion. A custom-designed spectrometer based on a Czerny Turner configuration was implemented to achieve an imaging depth of 1 mm. Experimentally measured axial resolution was 1.1 μm in corneal tissue and had a good agreement with the theoretically calculated resolution from the envelope of the spectral interference fringes. In vivo imaging was carried out and thin corneal layers such as the tear film and the Bowman’s layer were quantified in normal, keratoconus, and contact lens wearing eyes, indicating the system’s suitability for several ophthalmic applications.

ABSTRACT

N. Akopian, L. Wang, A. Rastelli, O. G. Schmidt & V. Zwiller  

ABSTRACT

Labruyère, A.; Leproux, P.; Couderc, V.; Tombelaine, V.; Kobelke, J.; Schuster, K.; Bartelt, H.; Hilaire, S.; Huss, G.; Mélin, G.; XLIM Res. Inst., Univ. of Limoges, Limoges, France

ABSTRACT

We demonstrate efficient broadband four-wave-mixing (FWM) generation at the particular frequency detuning of ~150 THz from a 1064-nm sub-nanosecond laser pump in innovative structured-core germanium-oxide (GeO₂)-doped photonic crystal fibers (PCFs). Remarkably, the latter PCF has a small-diameter highly concentrated germanium rod in the core center that enables fine tuning of the FWM wavelengths. The generated anti-Stokes radiation at ~700 nm is subsequently used as secondary pump for generating a bright visible supercontinuum in the fundamental mode from 370 nm to beyond 1750 nm, when splicing the GeO₂-doped PCF to a pure-silica PCF, whose zero-dispersion wavelength is set in-between the pump and anti-Stokes wavelengths, consistently with the standard dual-wavelength pumping scheme.

Rémi Soummer
Space Telescope Science Institute (USA) and American Museum of Natural History (USA)

Anand Sivaramakrishnan, Ben R. Oppenheimer, Robin Roberts,Douglas Brenner, Emily Griffiths, and Jacob Mey
American Museum of Natural History (USA)

Alexis Carlotti
Univ. de Nice Sophia Antipolis (France)

Laurent Pueyo and Kent Wallace
Jet Propulsion Lab. (USA)

Bruce Macintosh, Brian Bauman, and David Palmer
Lawrence Livermore National Lab. (USA)

Les Saddlemyer, Darren Erickson, Kris Caputa, and Christian Marois Herzberg
Institute of Astrophysics, National Research Council Canada (Canada)

Christophe Dorrer
Aktiwave LLC (USA)

ABSTRACT

The Gemini Planet Imager (GPI) is a new facility instrument to be commissioned at the 8-m Gemini South telescope in early 2011. It combines of several subsystems including a 1500 subaperture Extreme Adaptive Optics system, an Apodized Pupil Lyot Coronagraph, a near-infrared high-accuracy interferometric wavefront sensor, and an Integral Field Unit Spectrograph, which serves as the science instrument. GPI's main scientific goal is to detect and characterize relatively young (<2GYr), self luminous planets with planet-star brightness ratios of ≤ 10^-7 in the near infrared. Here we present an overview of the coronagraph subsystem, which includes a pupil apodization, a hard-edged focal plane mask and a Lyot stop. We discuss designs optimization, masks fabrication and testing. We describe a near infrared testbed, which achieved broadband contrast (H-band) below 10^-6 at separations > 5λ/D, without active wavefront control (no deformable mirror). We use Fresnel propagation modeling to analyze the testbed results.

© 2009 COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Vincent Tombelaine, Alexis Labruyère, Jens Kobelke, Kay Schuster, Volker Reichel, Philippe Leproux, Vincent Couderc, Raphaël Jamier, and Hartmut Bartelt

ABSTRACT

We report about a new type of nonlinear photonic crystal fibers allowing broadband four-wave mixing and supercontinuum generation. The microstructured optical fiber has a structured core consisting of a rod of highly nonlinear glass material inserted in a silica tube. This particular structure enables four wave mixing processes with very large frequency detuning (>135 THz), which permitted the generation of a wide supercontinuum spectrum extending over 1650 nm after 2.15 m of propagation length. The comparison with results obtained from germanium-doped holey fibers confirms the important role of the rod material properties regarding nonlinear process and dispersion.

© 2009 OSA

Vincent Tombelaine, Christelle Lesvigne, Philippe Leproux, Ludovic Grossard, Vincent Couderc, Jean-Louis Auguste, Jean-Marc Blondy, Guillaume Huss, and Paul-Henri Pioger

ABSTRACT

Second harmonic generation in an air-silica microstructured optical fiber pumped by subnanosecond pulses is used in order to initiate modulation instability processes in normal and anomalous dispersion regimes. This allows us to generate an ultra wide and flat supercontinuum (350-1750 nm), covering the entire transparency window of silica and exhibiting a singlemode transverse profile in visible range.

© 2005 Optical Society of America

Pierre-Alain Champert, Vincent Couderc, Philippe Leproux, Sébastien Février, Vincent Tombelaine, Laurent Labonté, Philippe Roy, Claude Froehly, and Philippe Nérin

ABSTRACT

We report on the experimental demonstration of a white-light supercontinuum generation in normally dispersive singlemode air-silica microstructured fiber. We demonstrate that the simultaneous excitation of the microstuctured fiber in its normal and anomalous dispersion regimes using the fundamental and second harmonic signals of a passively Q-switched microchip laser leads to a homogeneous supercontinuum in the visible range. This pumping scheme allows the suppression of the cascaded Raman effect predominance in favor of an efficient spectrum broadening induced by parametric phenomena. A flat supercontinuum extended from 400 to 700 nm is achieved.

© 2004 Optical Society of America

Akira Tanaka ; Ryo Okamoto ; Hwan Hong Lim ; Shanthi Subashchandran ; Masayuki Okano ; Labao Zhang ; Lin Kang ; Jian Chen ; Peiheng Wu ; Toru Hirohata ; Sunao Kurimura ; Shigeki Takeuchi.

Compressing the temporal correlation of two photons to the monocycle regime (3.56 fs, center wavelength: 1064 nm) is expected to open up new perspectives in quantum metrology, allowing applications such as submicron quantum optical coherence tomography and novel nonlinear optical experiments. To achieve this, the two-photon state must essentially be ultra-broadband in the frequency domain and ultra-short in the time domain. Here, we report the successful generation of such ultra-broadband, frequency-correlated two-photon states via type-0, cw-pumped (532 nm) spontaneous parametric down conversion using four PPMgSLT crystals with different chirp rates of their poling periods. For the collinear condition, single-photon spectra are detected using a Si-CCD and an InGaAs photodiode array with a monochromator, while for a noncollinear condition, an NbN meander-type superconducting single photon detector (SNSPD) and an InP/GaAs photomultiplier tube (PMT) with a laser line Bragg tunable bandpass filter are used. The broadband sensitivity of the SNSPD and PMT in the near-infrared wavelength range enable singleshot observations with a maximum bandwidth of 820 nm among the four samples. Such spectra can in principle achieve a temporal correlation as short as 1.2 cycles (4.4 fs) with the use of appropriate phase compensation, which can be measured using the sum-frequency signal. We also discuss several detection strategies for measuring coincidence counts in the presence of wavelength-dependent optical elements as a step towards frequency correlation measurements. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE).

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Magneto-optical (MO) effects are used as tools for probing the magnetization reversal characteristics of a wide range of sample types, and as an effective way to modify the polarization of light via induced magnetization state in samples.