Photonic Quantum Wells Research Articles

Resonant photonic states of quasi one-dimensional photonic quantum well in a rectangular waveguide

We have demonstrated a calculation of the resonant photonic states of quasi one dimensional photonic quantum well for the transverse electric (TE) and transverse magnetic (TM) modes in a rectangular waveguide. The photonic crystal heterostuctures are composed of two different photonic crystals as (AB)m(CD)n(AB)m . In order to solve the resonant photonic states, it is necessary to calculate the transmission functions of TE modes and TM modes. In this work, we consider the propagation of microwaves in photonic crystal heterostructures in our simulation model. The positions and number of the resonant photonic states can be adjusted by the widths of photonic quantum wells. The degenerate resonant photonic states are not existed for both the TE and TM modes, respectively. These results are useful applications in photonic quantum devices and nano technologies.

Analysis of defect states in optical microcavities based on the photonic quantum well structure

The defect states in optical microcavities are demonstrated to be related to the different confinement states by analyzing the photonic band structure of the equivalent photonic quantumwell structure consisted of a photonic well confined by photonic barriers. Our results indicate that the defect states in optical microcavities could be divided namely into the localized, pseudo-localized, and non-localized modes, and explain the relationship between the localized states in optical microcavities and confinement effects of the electric field in the defect layers.

Near-infrared tunable narrow filter in a periodic multi-nanolayer doped by a superconductor photonic quantum-well.

The transfer matrix method is employed to theoretically investigate the near-infrared (NIR) narrow filter properties in a one-dimensional defective symmetric photonic crystal with a superconductor photonic quantum-well defect (PQW). The study investigates how the wavelength of the defect mode is affected by the stack number of the PQW defect structure, the thicknesses of PQW layers, the polarization, and the angle of incidence as well as the operating temperature. The results also show that the period of the PQW defect structure and the number of defect modes are independent of one another. This result differs from that of studies conducted on a common dielectric or metamaterial defect. It is noted that with an increase in the number of the defect period, the thickness of the superconductor layer, and the angle of incidence, the defect mode shows a blue-shift for both wave polarizations. On the other hand, an opposite trend is observed as the thickness of the air layer and the operating temperature increase. The results also reveal that new tunable narrow filters and optical communication devices can be achieved at NIR region in this proposed structure.

Characteristics of light tunneling channel in one-dimensional photonic quantum well

The light tunneling channel characteristics of one-dimensional photonic crystal with single-barrier quantum well are studied by transfer matrix method. Light tunneling channels with 100% transmittance was found, and characteristics of these channels will be changed by structure parameters, such as lattice constant, incident angle. Specifically speaking, the results show that as t (periodic number of the well layer) increases the light tunneling channel number increases by the laws of t−1, however as s (periodic number of the barrier layer) increases the light tunneling channel number is unchanged. As the incidence angle becomes larger, the channel width become narrower, however the light tunneling channel number is unchanged. While the smaller the lattice constant is, the narrower the channel width is. These characteristics above can provide guidance for designing new high quality quantum optical devices, for example, multi-channel optical filter with adjustable channel.

Resonant modes in photonic double quantum well structures with single-negative materials

The transmission spectra of the model of photonic double quantum well consisting of two photonic crystals with two different single-negative materials are calculated by the transfer matrix method. It is found that these resonance modes split into pairs, owing to a coupling between two photonic wells. The distance of resonant modes can be controlled by the coupling strength between the two wells. It is observed that when two photonic quantum wells are far from each other, resonance modes appear as single peak. And the quality factors of the transmittance resonance peaks can be greatly improved by increasing the period number of outer barriers. The resonance modes are affected weakly by the incident angle and polarization. The effects of the losses coming from epsilon-negative and mu-negative materials on the resonance modes are also specifically explored, respectively.

Properties of one Dimensional Photonic Crystals with Defects Thickness and Temperature Dependence

The transmission properties of one dimensional photonic crystals with two defects having structures (HL)n(D1LD2L)m(HL)n, where m is the stack number of the Photonic Quantum Well (PQW) have been theoretically investigated by the transfer matrix method. The thickness and temperature dependence of the defect modes have been studied by considering Si and air as the high and low refractive index materials with GaAs and InSb as the two defects. For a defect lattice with m=1 (two defects) the two peaks due to defects are shifted towards the higher wavelength region, when the thickness of the defect layers is changed. Also, the transmittance peaks are shifted by 0.44nm/K and 0.50nm/K due to temperature variation. The above shifts for other cases (m ≠ 1 and n ≠ 1), have also been obtained. Part of these results is in qualitative agreement with the results available in the literature for other photonic crystals.

A label-free single photonic quantum well biosensor based on porous silicon for DNA detection

The single photonic quantum well (PQW) structures are successfully fabricated on p-type silicon wafer by electrochemical etching process, and are used for DNA detection firstly. The red shift of resonance peak is caused by the changing refractive index of PSi layer, which results from coupling of organic molecules into pores. When the porous silicon (PSi) based single PQW biosensors are immersed in complementary deoxyribonucleic acid (DNA) with different concentrations ranging from 0.625 μM to 10.000 μM, a good linear relationship is observed between the red shift of resonance peak and the complementary DNA concentration. Experimental results show that the detection sensitivity of PSi-based single PQW biosensors is 3.04 nm/μM with a detection limit of 32 nM for 16-base pair DNA oligonucleotides.

CONTROLLING TUNNELING MODES BY A PHOTONIC QUANTUM WELL STRUCTURE BASED ON ZERO EFFECTIVE PHASE GAP

Light propagation through one-dimensional photonic quantum well (PQW) structures consisting of single-negative (SNG) materials is investigated theoretically. It is found that, based on the zero-effective-phase gap mechanism, the resonant tunneling modes can be manipulated to realized multiple channeled filters which are not only weakly dependent on the incident angle and polarization, but also insensitive to the deviation of the photonic barrier thickness. These properties are advanced to conventional PQW structures and the physical reason for the remarkable features of the proposed PQW structure is analyzed.

ANALYSIS OF TRANSMISSION PROPERTIES IN A PHOTONIC QUANTUM WELL CONTAINING SUPERCONDUCTING MATERIALS

Properties of wave transmission in a photonic quantum well (PQW) structure containing superconducting materials are theoretically investigated. We consider two possible PQW structures, (AB) P (CD) Q (AB) P -asymmetric and (AB) P (CD) Q (BA) P -symmetric, where the host photonic crystal (PC) (AB) P is made of dielectrics, A = SrTiO3, B = Al2O3, and the PQW (CD) Q contains C = A and superconducting layer D = YBa2Cu3O7ix, a typical high-temperature superconducting thin fllm. Multiple transmission peaks can be seen within the photonic band gap (PBG) of (AB) P and the number of peaks is directly determined by the stack number of PQW, i.e., it equals Q-1. Additionally, the results show that symmetric PQW structure is preferable to the design of a multichannel transmission fllter. The efiect of stack number of photonic barrier is also illustrated. Such a fllter operating at terahertz with feature of multiple channels is of technical use in superconducting optoelectronic applications.

TUNABLE OUTPUT OF SECOND HARMONIC GENERATIONS IN PHOTONIC QUANTUM WELL STRUCTURES MADE OF NONLINEAR MATERIAL

We have studied multiple wavelength second harmonic generation (SHG) in one-dimensional multiple photonic quantum-wells (PQWs) structure made of linear and nonlinear material. The numerical simulations show that the devised sample can achieve simultaneously multiple wavelength SHG with nearly identical conversion efficiency by the modulation of both the linear and nonlinear optical coefficient. The fundamental wave frequencies are aimed at the defect states by modulating the linear optical coefficient. The optimal arrangement of the polarization directions of the ferroelectric domains in multiple PQWs are determined by simulated annealing method. By tuning the polarization directions of the domains, the conversion efficiencies of "forward" and "backward" for multiple wavelength SHG can be flexibly modulated.

Resonant modes and inter-well coupling in photonic double quantum well structures with single-negative materials

We investigate the resonance tunneling modes of photonic double quantum well made of two photonic crystals with two different single-negative materials. It is found that these resonance modes split pairs, due to a coupling between two photonic wells. It is observed that when two photonic quantum wells are far away from each other, resonance modes appear as a single peak. And the quality factors of the transmittance resonance peaks can be greatly improved by increasing the period number of the outer barrier. The effects of the losses coming from ENG and MNG materials on the resonance modes are also specifically explored.

Temperature-Dependent Tunable Photonic Channel Filter

In the present communication, we studied the 1-D photonic quantum-well (PQW) structure for the photonic channel filter. The PQW structure consists of a defect layer in Si/air multilayered regular 1-D photonic crystal. The extension of the work shows the temperature-dependent tuning in the channel filter.

Tunable Multichannel Filter in a Photonic Crystal Containing Semiconductor Photonic Quantum Well

A tunable multichannel filter in the finite photonic crystal (PC) containing photonic quantum well (PQW) as a defect is proposed. The symmetric structure (AB) <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i> (CD) <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> ( BA) <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i> and the asymmetric structure (AB) <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i> (CD) <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> (AB) <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i> are considered in this work. Here, the host PC of (AB) <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">P</i> is made of Si for layer A and of SiO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> for layer B. In the PQW, (CD) <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> , C also is Si, but D is an extrinsic semiconductor, <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> -type silicon ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> -Si). With the use of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> -Si, it is found that both structures can function as a tunable multichannel filter in the infrared region. The number of channels is equal to <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> + 1 in the symmetric structure, whereas it is <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Q</i> for the asymmetric one. The positions of multiple resonant peaks can be tuned by the variation in the impurity concentration of <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> -Si. The proposed filter could be used to design the wavelength division multiplexer filter that is of technical use in optical communications.

Resonance Modes in Multiple Quantum Wells Structure of Two-Dimensional Photonic Crystal

We have theoretically discussed the resonance modes in a two-dimensional photonic multiple quantum wells structure (QWs) consists of one photonic crystal with square lattice of parallel dielectric circular columns in air and some layers of columns are removed at constant intervals. The generation and frequency split of resonance modes are observed and explained with tight-binding approach. The effect of the interaction distance on the frequency split is also discussed.

Temperature dependence of active photonic band gap in bragg-spaced quantum wells

A novel all-optical polarization switch of active photonic band gap structure based on non-resonant optical Stark effect bragg-spaced quantum wells was investigated and it could be compatible with the optical communication system. The theory is based on InGaAsP/InP Bragg-spaced quantum wells (BSQWs). Mainly through the design of the InGaAsP well layer component and InP barrier thickness to make the quantum-period cycle meet the bragg condition and the bragg frequency is equal to re-hole exciton resonance frequency. When a spectrally narrow control pulse is tuned within the forbidden gap, such BSQWs have been shown to exhibit large optical nonlinearities and ps recovery times, which can form T hz switch. However, the exciton binding energy of InGaAsP will be automatically separate at room temperature, so the effect of all-optical polarization switching of active photonic band gap bragg structure quantum wells can only be studied at low temperature. By a large number of experiments, we tested part of the material parameters of BSQWs in the temperature range 10-300K. On this basis, the InGaAsP and InP refractive index changes with wavelength, InP thermal expansion coefficient are studied and a relationship equation is established. Experimental results show that the bragg reflection spectra with temperature mainly is effected by InP refractive index changes with temperature. Our theoretical study and experiment are an instruction as a reference in the designs and experiments of future practical optical switches.

Use of photonic quantum well as tunable defect in multilayer narrowband reflection-and-transmission filter

By using a photonic quantum well (PQW) as a tunable defect layer, a theoretical analysis on the optical properties in a multilayer narrowband reflection-and-transmission filter can be given. It is found that the resonant peaks in the reflection and transmission spectra are shifted to shorter wavelengths as the number of periods in the PQW increases. The shifting feature is more salient if the QW is deeper, that is, the refractive index contrast in the constituents of the PQW is increased. This novel design provides an alternative for achieving a tunable filter instead of using the usual electrooptical defect.

Generation of bonding and antibonding photonic modes in laser-induced photonic double quantum wells

We study generation of photonic modes, including bonding and antibonding modes, in a laser-induced photonic double quantum well. Such a quantum well is formed via illumination of a special type of a photonic waveguide structure (photonic superstructure) with a laser field. Striking similarities between states of electrons in electronic double quantum wells and photonic modes in symmetric and asymmetric photonic double quantum wells are predicted. We show that in such photonic quantum wells one can use the laser field to control the degree of mixing of the bonding and antibonding photonic modes (subbands), forming pure to strongly mixed transmission states.

Resonant Tunneling in Photonic Double Quantum Well Heterostructures.

Here, we study the resonant photonic states of photonic double quantum well (PDQW) heterostructures composed of two different photonic crystals. The heterostructure is denoted as B/A/B/A/B, where photonic crystals A and B act as photonic wells and barriers, respectively. The resulting band structure causes photons to become confined within the wells, where they occupy discrete quantized states. We have obtained an expression for the transmission coefficient of the PDQW heterostructure using the transfer matrix method and have found that resonant states exist within the photonic wells. These resonant states occur in split pairs, due to a coupling between degenerate states shared by each of the photonic wells. It is observed that when the resonance energy lies at a bound photonic state and the two photonic quantum wells are far away from each other, resonant states appear in the transmission spectrum of the PDQW as single peaks. However, when the wells are brought closer together, coupling between bound photonic states causes an energy-splitting effect, and the transmitted states each have two peaks. Essentially, this means that the system can be switched between single and double transparent states. We have also observed that the total number of resonant states can be controlled by varying the width of the photonic wells, and the quality factor of transmitted peaks can be drastically improved by increasing the thickness of the outer photonic barriers. It is anticipated that the resonant states described here can be used to develop new types of photonic-switching devices, optical filters, and other optoelectronic devices.

OMNIDIRECTIONAL FILTERING BASED ON ZERO-AVERAGED REFRACTIVE INDEX GAP IN PHOTONIC QUANTUM WELL STRUCTURES

A photonic quantum well (PQW) structure based on the zero-averaged refractive index gap is constructed and the transmission properties are investigated. Quantized confined photonic states resulting from the photonic confinement effect are observed. We find that the resonant transmissions are not only weakly dependent on the incident angle but also insensitive to polarization of light. More importantly, the number of the confined photonic states can be controlled by simply adjusting the cell number of the well photonic crystal. It is shown that strong field localization is found when the well photonic crystal consists of positive-index material or single negative material. Particularly for the PQW structure containing single negative material, the field in the well region can be highly enhanced by modulating the size of the well photonic crystal. These peculiar features make this PQW structure superior to the conventional PQW structure in potential applications such as omnidirectional filtering and optical bistable switching.

Photonic valence/conduction subbands in optically generated photonic quantum wells: Tunable optical-delay line application

It has been shown that, in the absence of a control laser field, functional photonic superstructures can act as homogeneous photonic band gap structures formed via uniform corrugations of their background refractive indexes. When some sections of these structures are illuminated with such a laser, those sections become resonant (active) photonic band structures with higher refractive index contrast, forming photonic heterostructures. In this paper we study how by controlling the phase of quantum interference processes in such structures one can control alignment of such heterostructures, coherently generating photonic quantum wells with either conduction- or valencelike subbands (resonant transmission states). We show the energies of these subbands can be tuned by the control laser and demonstrate that their longitudinal mode profiles follow one-by-one correspondence with the envelope functions of the electron or hole subbands in electronic quantum well structures. In particular, we show how such photonic quantum wells can act as optically tunable time-delay lines, capable of increasing delay of a signal passing through them significantly via laser-induced control of optical confinements of the photonic subbands.