skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Vertical cavity lasing from melt-grown crystals of cyano-substituted thiophene/phenylene co-oligomer

Abstract

Vertical-cavity organic lasers are fabricated with melt-grown crystals of a cyano-substituted thiophene-phenylene co-oligomer. Due to lying molecular orientation, surface-emitting lasing is achieved even in the half-cavity crystal grown on a distributed Bragg reflector (DBR) under optical pumping at room temperature. Anticrossing splits in angle-resolved photoluminescence spectra suggest the formation of exciton-polaritons between the cavity photons and the confined Frenkel excitons. By constructing the full-cavity structure sandwiched between the top and bottom DBRs, the lasing threshold is reduced to one order, which is as low as that of the half cavity. Around the threshold, the time profile of the full-cavity emission is collapsed to a pulsed shape accompanied by a finite turn-on delay. We discuss these observed characteristics in terms of a polariton contribution to the conventional photon lasing.

Authors:
;  [1]; ; ; ;  [2];  [3]
  1. Graduate School of Materials Science, Nara Institute of Science and Technology (NAIST), 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan)
  2. Graduate School of Science and Technology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585 (Japan)
  3. Electronics and Photonics Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568 (Japan)
Publication Date:
OSTI Identifier:
22485951
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 107; Journal Issue: 16; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; CRYSTALS; EXCITONS; LASERS; OPTICAL PUMPING; ORIENTATION; PHOTOLUMINESCENCE; PHOTONS; POLARONS; POLYCYCLIC SULFUR HETEROCYCLES; PULSE SHAPERS; SPECTRA; SURFACES; TEMPERATURE RANGE 0273-0400 K; THIOPHENE

Citation Formats

Tanaka, Yosuke, Yanagi, Hisao, E-mail: yanagi@ms.naist.jp, Goto, Kaname, Yamashita, Kenichi, Yamao, Takeshi, Hotta, Shu, and Sasaki, Fumio. Vertical cavity lasing from melt-grown crystals of cyano-substituted thiophene/phenylene co-oligomer. United States: N. p., 2015. Web. doi:10.1063/1.4934588.
Tanaka, Yosuke, Yanagi, Hisao, E-mail: yanagi@ms.naist.jp, Goto, Kaname, Yamashita, Kenichi, Yamao, Takeshi, Hotta, Shu, & Sasaki, Fumio. Vertical cavity lasing from melt-grown crystals of cyano-substituted thiophene/phenylene co-oligomer. United States. doi:10.1063/1.4934588.
Tanaka, Yosuke, Yanagi, Hisao, E-mail: yanagi@ms.naist.jp, Goto, Kaname, Yamashita, Kenichi, Yamao, Takeshi, Hotta, Shu, and Sasaki, Fumio. 2015. "Vertical cavity lasing from melt-grown crystals of cyano-substituted thiophene/phenylene co-oligomer". United States. doi:10.1063/1.4934588.
@article{osti_22485951,
title = {Vertical cavity lasing from melt-grown crystals of cyano-substituted thiophene/phenylene co-oligomer},
author = {Tanaka, Yosuke and Yanagi, Hisao, E-mail: yanagi@ms.naist.jp and Goto, Kaname and Yamashita, Kenichi and Yamao, Takeshi and Hotta, Shu and Sasaki, Fumio},
abstractNote = {Vertical-cavity organic lasers are fabricated with melt-grown crystals of a cyano-substituted thiophene-phenylene co-oligomer. Due to lying molecular orientation, surface-emitting lasing is achieved even in the half-cavity crystal grown on a distributed Bragg reflector (DBR) under optical pumping at room temperature. Anticrossing splits in angle-resolved photoluminescence spectra suggest the formation of exciton-polaritons between the cavity photons and the confined Frenkel excitons. By constructing the full-cavity structure sandwiched between the top and bottom DBRs, the lasing threshold is reduced to one order, which is as low as that of the half cavity. Around the threshold, the time profile of the full-cavity emission is collapsed to a pulsed shape accompanied by a finite turn-on delay. We discuss these observed characteristics in terms of a polariton contribution to the conventional photon lasing.},
doi = {10.1063/1.4934588},
journal = {Applied Physics Letters},
number = 16,
volume = 107,
place = {United States},
year = 2015,
month =
}
  • For highly divergent emission of broad-area vertical-cavity surface-emitting lasers, a rotation of the polarization direction by up to 90 deg. occurs when the pump rate approaches the lasing threshold. Well below threshold the polarization is parallel to the direction of the transverse wave vector and is determined by the transmissive properties of the Bragg reflectors that form the cavity mirrors. In contrast, near-threshold and above-threshold emission is more affected by the reflective properties of the reflectors and is predominantly perpendicular to the direction of transverse wave vectors. Two qualitatively different types of polarization transition are demonstrated: an abrupt transition, wheremore » the light polarization vanishes at the point of the transition, and a smooth transition, where it is significantly nonzero during the transition.« less
  • Amplified Raman scattering was observed from single crystals of thiophene/phenylene co-oligomers (TPCOs). Under ns-pulsed excitation, the TPCO crystals exhibited amplified spontaneous emission (ASE) at resonant absorption wavelengths. With increasing excitation wavelength to the 0-0 absorption edge, the stimulated resonant Raman peaks appeared both in the 0-1 and 0-2 ASE band regions. When the excitation wavelength coincided with the 0-1 ASE band energy, the Raman peaks selectively appeared in the 0-2 ASE band. Such unusual enhancement of the 0-2 Raman scattering was ascribed to resonant stimulation via vibronic coupling with electronic transitions in the uniaxially oriented TPCO molecules.
  • The physicochemical conditions required for growing crystals of sodium--rare earth germanates and silicates with the olivine structure are found, and a number of single crystals are grown from solution in a melt. From one of these, namely NaGdGeO/sub 4/--Nd/sup 3 +/, at 300 K, stimulated emission is obtained with a low excitation threshold in two generation channels, /sup 4/F/sub 3/2/..-->../sup 4/I/sub 11/2/ and /sup 4/F/sub 3/2/..-->../sup 4/I/sub 13/2/. Spectroscopic investigations reveal that this series of compounds has specific luminescent characteristics and represents a new class of crystals for exciting laser generation of Nd/sup 3 +/ ions.
  • The temperature dependence of the density, mobility, and lifetime of electrons, and the photoconductivity and cathodoluminescence spectra of gallium arsenide with different electron densities doped with germanium when single crystals are grown by the Czochralski method are investigated. An analysis of the scattering mechanism is given, and the acceptor and donor densities are determined. The acceptor-type capture levels are found from the temperature dependence of the electron lifetime. The results of a study of the cathodoluminescence spectra indicate the presence in the specimens of complex radiational recombination centers similar to germanium-atom complexes with inherent lattice defects.
  • The physical properties of compound semiconductors, including IV-VI crystals, are in many ways determined by the intrinsic lattice defects of their structure. The presence of these defects is, in large part, associated with the nonstoichiometry of real crystals. Therefore, controlling these properties reduces primarily to controlling the intrinsic-defect structure and the stoichiometry of crystals. For this purpose, a technique according to which gadolinium is added to the melt has recently been proposed and tested for growing lead telluride crystals. In this way, we obtained impurity free samples of PbTe, which were in many respects more perfect than their analogs preparedmore » using conventional approaches to controlling the defect structure. In this paper, we summarize data obtained in systematic studies of the effect of gadolinium on the quality of PbTe, PbSe, and Pb{sub 1{minus}x}-,Sn{sub x} crystals from the melt under various process conditions.« less