This article explores the modulation instability of a continuous or quasi-continuous weak probe p... more This article explores the modulation instability of a continuous or quasi-continuous weak probe pulse in a three-level asymmetric double quantum wells under an electromagnetically induced transparency regime, controlled by a strong laser beam. The dynamics of modulation instability reveals that the instability gain as well as its bandwidth is greatly influenced by control field Rabi frequency. The probe pulse is found to be almost stable against modulation instability for higher values of control field Rabi frequency. The results of this investigation may potentially apply for oscillation free generation of supercontinuum in quantum well nanostructures.
2014 IEEE Photonics Society Summer Topical Meeting Series, 2014
We have produced ≈20mW of mid-infrared super continuum spanning from 1750nm to ≈8000nm spanning u... more We have produced ≈20mW of mid-infrared super continuum spanning from 1750nm to ≈8000nm spanning using a 1cm long chalcogenide waveguide pumped by a 21MHz train of 320fs pulses at 4μm.
2013 International Conference on Microwave and Photonics (ICMAP), 2013
This paper presents a unique birefringent photonic crystal fiber, which promises to yield very hi... more This paper presents a unique birefringent photonic crystal fiber, which promises to yield very high birefringence. The FDTD method has been employed for characterization of its optical parameters. The fiber possesses anomalous dispersion. Several important fiber parameters such as birefringence, dispersion, effective V parameter and Walk-off have been investigated numerically.
ABSTRACT This paper presents the design of an index guided photonic crystal fiber which promises ... more ABSTRACT This paper presents the design of an index guided photonic crystal fiber which promises to yield very large birefringence (∼ 2.22 × 10−2 ). Important optical properties, such as birefringence, single modeness, optical confinement, fiber dispersion, walk-off, etc., have been studied employing numerical simulation through finite difference time domain scheme. The fiber also promises a very small walk-off near optical communication wavelength.
The paper presents a theoretical study of the modulation instability of a continuous or quasi-con... more The paper presents a theoretical study of the modulation instability of a continuous or quasi-continuous optical probe in a three level quantum well system under electromagnetically induced transparency. The modulation instability is affected by the control field detuning, as well as even-order dispersion and by the strength of Kerr (third-order) and quintic (fifth-order) nonlinearities. The fourth-order dispersion reduces the bandwidth over which modulation instability occurs, whereas the quintic nonlinearity saturates the growth of the modulation instability. Detuning the control field from resonance can significantly reduce the growth of the modulation instability at both low and high power levels. At low powers, the system becomes stable against modulation instability for small detuning of the control field and at high powers modulation instability disappears for larger detuning.
Abstract Higher order nonlinear susceptibilities have been investigated in a three level asymmetr... more Abstract Higher order nonlinear susceptibilities have been investigated in a three level asymmetric multiple quantum well nanostructure wherein a probe pulse and a control laser beam are interacting in Λ -type configuration in the regime of electromagnetically induced transparency. We have identified the existence of giant fifth order susceptibility as large as ∼ 10 − 24 m 4 / V 4 at a pump wavelength 5.128 μ m . By changing the value of the Rabi frequency or the pump detuning the peak value of the susceptibility can be obtained at different pump frequency. With the introduction of detuning of the control field, the antisymmetric property of the fifth order susceptibility disappears. The group velocity of the probe field is reported to be slowed down by three order of magnitude in comparison to that of the speed of light in vacuum. These results may have potential applications in optoelectronic devices.
Abstract In this paper, employing numerical simulation, we examine the possibility of generation ... more Abstract In this paper, employing numerical simulation, we examine the possibility of generation of optical supercontinuum (SC) in a multiple quantum well (MQW) system facilitated by electromagnetically induced transparency. Within the transparency window created by a control laser beam in a MQW, another probe pulse experiences negligible loss and large optical non-linearity that has been exploited to obtain the optical SC. With 1.0 pico-second ‘sech’ probe pulses of 500 W peak power at wavelength 739.7 nm, the numerically simulated SC spectrum at the end of the 9.377 μm long MQW extends from 550 to 1000 nm. The spectrum is asymmetric, contains large number of oscillations which is attributed to the nonlinearity induced self-phase modulation and modulation instability. This investigation may lead to the fabrication of on-chip SC sources that can be easily integrated with other semiconductor devices.
This paper presents the design of an index guided highly birefringent photonic crystal fiber whic... more This paper presents the design of an index guided highly birefringent photonic crystal fiber which promises to yield very large birefringence (~3.33 × 10) at 1550nm and (~1.75 × 10) at 1064nm as well as large effective nonlinearity (~80). Optical supercontinuum generation in the proposed fiber using a 1064 nm pump source with peak power of 1kW has been also presented. Finite difference time domain method (FDTD) has been employed to examine the optical properties such as fiber birefringence, mode field, V-parameter, walk-off and optical nonlinearity, while the 2 Split-step Fourier method is used to solve the nonlinear Schrödinger equation felicitating the study of supercontinuum generation. Simulation results indicate that horizontal input pulse yields superior continuum in comparison to that of the vertically polarized input. However, the broadening of the continuum is about 1450 nm in case of horizontally polarized input light whereas it is approximately 2350 nm for vertically polarized. Recently, Rakhi et. al. [32] have reported very large birefringence (~ 5.45 × 10) in
Optik - International Journal for Light and Electron Optics, 2016
Abstract This paper presents broadband supercontinuum generation in photonic crystal fibers emplo... more Abstract This paper presents broadband supercontinuum generation in photonic crystal fibers employing cosh-Gaussian pulses. The supercontinuum spectrum of cosh-Gaussian pulses consists of a large number of internal oscillations which increases with the increase in the value of cosh factor. Unlike the supercontinuum spectra created by Gaussian pulses, which consists of two distinct minima, the spectra created by cosh-Gaussian pulses of equal peak power and pulse duration characterized by virtually flat and broadband supercontinuum. Improvement in the flatness of the generated supercontinuum increases with the increase in the value of cosh factor.
Mid-infrared spectral broadening is of great scientific and technological interest, which till da... more Mid-infrared spectral broadening is of great scientific and technological interest, which till date is mainly achieved using non-silica glass fibers, primarily made of tellurite, fluoride and chalcogenide glasses. We investigate broadband mid-infrared supercontinuum generation at very low power in semiconductor multiple quantum well (MQW) systems facilitated by electromagnetically induced transparency. 100 femto-seconds pulses of peak power close to a Watt have been launched in the electromagnetically induced transparency window of a 30 period 1.374 {\mu}m long MQW system. Broadband supercontinuum spectra, attributed to self phase modulation and modulation instability, is achievable at the end of the MQW system. The central part of the spectra is dominated by several dips and the far infra-red part of the spectra is more broadened in comparison to the infra-red portion. Key advantage of the proposed scheme is that the supercontinuum source could be easily integrated with other semic...
Enhancement of higher order nonlinear susceptibilities are investigated in three level quantum we... more Enhancement of higher order nonlinear susceptibilities are investigated in three level quantum well with a ladder configuration in the regime of electromagnetically induced transparency. We have identified the existence of giant third and fifth order nonlinear susceptibilities of the order ~10-22 m4/V4 at pump wavelength of 9.6 μm. The group velocity is reported to be slowed down by 104 times compared to the speed of light in vacuum.
This article explores the modulation instability of a continuous or quasi-continuous weak probe p... more This article explores the modulation instability of a continuous or quasi-continuous weak probe pulse in a three-level asymmetric double quantum wells under an electromagnetically induced transparency regime, controlled by a strong laser beam. The dynamics of modulation instability reveals that the instability gain as well as its bandwidth is greatly influenced by control field Rabi frequency. The probe pulse is found to be almost stable against modulation instability for higher values of control field Rabi frequency. The results of this investigation may potentially apply for oscillation free generation of supercontinuum in quantum well nanostructures.
2014 IEEE Photonics Society Summer Topical Meeting Series, 2014
We have produced ≈20mW of mid-infrared super continuum spanning from 1750nm to ≈8000nm spanning u... more We have produced ≈20mW of mid-infrared super continuum spanning from 1750nm to ≈8000nm spanning using a 1cm long chalcogenide waveguide pumped by a 21MHz train of 320fs pulses at 4μm.
2013 International Conference on Microwave and Photonics (ICMAP), 2013
This paper presents a unique birefringent photonic crystal fiber, which promises to yield very hi... more This paper presents a unique birefringent photonic crystal fiber, which promises to yield very high birefringence. The FDTD method has been employed for characterization of its optical parameters. The fiber possesses anomalous dispersion. Several important fiber parameters such as birefringence, dispersion, effective V parameter and Walk-off have been investigated numerically.
ABSTRACT This paper presents the design of an index guided photonic crystal fiber which promises ... more ABSTRACT This paper presents the design of an index guided photonic crystal fiber which promises to yield very large birefringence (∼ 2.22 × 10−2 ). Important optical properties, such as birefringence, single modeness, optical confinement, fiber dispersion, walk-off, etc., have been studied employing numerical simulation through finite difference time domain scheme. The fiber also promises a very small walk-off near optical communication wavelength.
The paper presents a theoretical study of the modulation instability of a continuous or quasi-con... more The paper presents a theoretical study of the modulation instability of a continuous or quasi-continuous optical probe in a three level quantum well system under electromagnetically induced transparency. The modulation instability is affected by the control field detuning, as well as even-order dispersion and by the strength of Kerr (third-order) and quintic (fifth-order) nonlinearities. The fourth-order dispersion reduces the bandwidth over which modulation instability occurs, whereas the quintic nonlinearity saturates the growth of the modulation instability. Detuning the control field from resonance can significantly reduce the growth of the modulation instability at both low and high power levels. At low powers, the system becomes stable against modulation instability for small detuning of the control field and at high powers modulation instability disappears for larger detuning.
Abstract Higher order nonlinear susceptibilities have been investigated in a three level asymmetr... more Abstract Higher order nonlinear susceptibilities have been investigated in a three level asymmetric multiple quantum well nanostructure wherein a probe pulse and a control laser beam are interacting in Λ -type configuration in the regime of electromagnetically induced transparency. We have identified the existence of giant fifth order susceptibility as large as ∼ 10 − 24 m 4 / V 4 at a pump wavelength 5.128 μ m . By changing the value of the Rabi frequency or the pump detuning the peak value of the susceptibility can be obtained at different pump frequency. With the introduction of detuning of the control field, the antisymmetric property of the fifth order susceptibility disappears. The group velocity of the probe field is reported to be slowed down by three order of magnitude in comparison to that of the speed of light in vacuum. These results may have potential applications in optoelectronic devices.
Abstract In this paper, employing numerical simulation, we examine the possibility of generation ... more Abstract In this paper, employing numerical simulation, we examine the possibility of generation of optical supercontinuum (SC) in a multiple quantum well (MQW) system facilitated by electromagnetically induced transparency. Within the transparency window created by a control laser beam in a MQW, another probe pulse experiences negligible loss and large optical non-linearity that has been exploited to obtain the optical SC. With 1.0 pico-second ‘sech’ probe pulses of 500 W peak power at wavelength 739.7 nm, the numerically simulated SC spectrum at the end of the 9.377 μm long MQW extends from 550 to 1000 nm. The spectrum is asymmetric, contains large number of oscillations which is attributed to the nonlinearity induced self-phase modulation and modulation instability. This investigation may lead to the fabrication of on-chip SC sources that can be easily integrated with other semiconductor devices.
This paper presents the design of an index guided highly birefringent photonic crystal fiber whic... more This paper presents the design of an index guided highly birefringent photonic crystal fiber which promises to yield very large birefringence (~3.33 × 10) at 1550nm and (~1.75 × 10) at 1064nm as well as large effective nonlinearity (~80). Optical supercontinuum generation in the proposed fiber using a 1064 nm pump source with peak power of 1kW has been also presented. Finite difference time domain method (FDTD) has been employed to examine the optical properties such as fiber birefringence, mode field, V-parameter, walk-off and optical nonlinearity, while the 2 Split-step Fourier method is used to solve the nonlinear Schrödinger equation felicitating the study of supercontinuum generation. Simulation results indicate that horizontal input pulse yields superior continuum in comparison to that of the vertically polarized input. However, the broadening of the continuum is about 1450 nm in case of horizontally polarized input light whereas it is approximately 2350 nm for vertically polarized. Recently, Rakhi et. al. [32] have reported very large birefringence (~ 5.45 × 10) in
Optik - International Journal for Light and Electron Optics, 2016
Abstract This paper presents broadband supercontinuum generation in photonic crystal fibers emplo... more Abstract This paper presents broadband supercontinuum generation in photonic crystal fibers employing cosh-Gaussian pulses. The supercontinuum spectrum of cosh-Gaussian pulses consists of a large number of internal oscillations which increases with the increase in the value of cosh factor. Unlike the supercontinuum spectra created by Gaussian pulses, which consists of two distinct minima, the spectra created by cosh-Gaussian pulses of equal peak power and pulse duration characterized by virtually flat and broadband supercontinuum. Improvement in the flatness of the generated supercontinuum increases with the increase in the value of cosh factor.
Mid-infrared spectral broadening is of great scientific and technological interest, which till da... more Mid-infrared spectral broadening is of great scientific and technological interest, which till date is mainly achieved using non-silica glass fibers, primarily made of tellurite, fluoride and chalcogenide glasses. We investigate broadband mid-infrared supercontinuum generation at very low power in semiconductor multiple quantum well (MQW) systems facilitated by electromagnetically induced transparency. 100 femto-seconds pulses of peak power close to a Watt have been launched in the electromagnetically induced transparency window of a 30 period 1.374 {\mu}m long MQW system. Broadband supercontinuum spectra, attributed to self phase modulation and modulation instability, is achievable at the end of the MQW system. The central part of the spectra is dominated by several dips and the far infra-red part of the spectra is more broadened in comparison to the infra-red portion. Key advantage of the proposed scheme is that the supercontinuum source could be easily integrated with other semic...
Enhancement of higher order nonlinear susceptibilities are investigated in three level quantum we... more Enhancement of higher order nonlinear susceptibilities are investigated in three level quantum well with a ladder configuration in the regime of electromagnetically induced transparency. We have identified the existence of giant third and fifth order nonlinear susceptibilities of the order ~10-22 m4/V4 at pump wavelength of 9.6 μm. The group velocity is reported to be slowed down by 104 times compared to the speed of light in vacuum.
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Papers by Nitu Borgohain