P. Kelkar
Brown University
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Publication
Featured researches published by P. Kelkar.
Applied Physics Letters | 1995
H. Jeon; V. Kozlov; P. Kelkar; A. V. Nurmikko; C.-C. Chu; D. C. Grillo; J. Han; G. C. Hua; R. L. Gunshor
Surface emitting laser operation at room temperature at λ=496 nm by ps pulsed optical injection has been demonstrated in a II–VI separate confinement heterostructure containing three 80 A thick (Zn,Cd)Se quantum wells (QW). The vertical cavity was formed by low loss, dielectric, distributed Bragg mirrors, yielding a quality factor for the structure of approximately Q≊2000. The room‐temperature threshold excitation corresponds to an absorbed optical energy density of 1.4 μJ/cm2 or, equivalently, to an estimated electron‐hole pair density of 1×1012 cm−2. At T=200 K, quasicontinuous wave operation was obtained at an average output power of up to 1 mW and an output/input conversion efficiency of 20%.
Journal of Crystal Growth | 1994
J. Ding; M. Hagerott; P. Kelkar; A. V. Nurmikko; D. C. Grillo; L. He; J. Han; R. L. Gunshor
Abstract Gain spectroscopy and population dynamics are investigated in ZnCdSe/ZnSSe/ZnMgSSe separate confinement heterostructure (SCH) diode lasers. Both steady state and time-resolved methods are applied to characterize the dense electron-hole pair gas in the ZnCdSe active quantum well (QW) region from 77 K to room temperature. Effects due to the carrier interaction with optical phonons and electron-hole Coulomb effects are discussed. A direct measurement of the carrier lifetime at pair densities under typical laser conditions has also been obtained.
Journal of Crystal Growth | 1998
P. Kelkar; A. V. Nurmikko; C.-C. Chu; J. Han; Wenzhou Chen; R. L. Gunshor
Abstract Enhanced light-matter coupling effects are striking in II–VI quantum well microresonators, with the normal mode (Rabi) splitting exceeding 10 meV per quantum well at the exciton resonance in ZnSe-based heterostructures. Such a dominating imprint of the mixed exciton-photon modes extends to high electron-hole pair densities, including the regime of vertical cavity laser operation. We present results from gain spectroscopy to show how the composite photon-exciton oscillator supplies optical gain for a laser operating beyond the conventional perturbative regime.
Physical Review B | 1995
P. Kelkar; V. Kozlov; H. Jeon; A. V. Nurmikko; C.-C. Chu; D. C. Grillo; J. Han; C. G. Hua; R. L. Gunshor
Physical Review B | 1994
J. Ding; M. Hagerott; P. Kelkar; A. V. Nurmikko; D. C. Grillo; L. He; J. Han; R. L. Gunshor
Physical Review B | 1997
P. Kelkar; V. Kozlov; A. V. Nurmikko; C.-C. Chu; J. Han; R. L. Gunshor
Electronics Letters | 1994
D. C. Grillo; J. Han; Mike D. Ringle; G. C. Hua; R. L. Gunshor; P. Kelkar; V. Kozlov; H. Jeon; A. V. Nurmikko
Physical Review B | 1996
V. Kozlov; P. Kelkar; A. V. Nurmikko; C.-C. Chu; D. C. Grillo; J. Han; C. G. Hua; R. L. Gunshor
Electronics Letters | 1993
A. Salokatve; H. Jeon; M. Hovinen; P. Kelkar; A. V. Nurmikko; D. C. Grillo; L. He; J. Han; Y. Fan; M. Ringle; R. L. Gunshor
Physical Review B | 1996
V. Kozlov; P. Kelkar; A. Vertikov; A. V. Nurmikko; C.-C. Chu; J. Han; C. G. Hua; R. L. Gunshor
