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A 22× reduction in laser pump threshold and a 23× enhancement in energy conversion have been demonstrated on a second order distributed feedback (DFB) laser using a resonant optical pumping (ROP) technique. The ROP scheme couples the excitation light into a distinct resonant mode of the laser cavity through the illuminating at a specific resonant i...
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... cross-sectional diagram (not to scale) of the DFB laser is shown in Fig. 1. A one- dimensional (1D) surface grating structure is formed in an ultraviolet curable polymer (UVCP) upon a flexible polyethylene-terephthalate (PET) substrate by nanoreplica molding [16,17]. The polymer grating surface is coated by horizontal dipping [18,19] with a high refractive index polymer layer, SU-8 (Microchem) doped with ...
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... reflection represents a resonance supported by the DFB cavity at a specific wavelength and a specific angle. A simulation tool (DiffractMOD, RSoft Design Group) based on the rigorous coupled-wave analysis (RCWA) technique aids the identification of the resonant modes. Figure 2 (a) shows a photonic band diagram for the structure described in Fig. 1, calculated for transverse electric (TE) modes in the 500 < λ < 680 nm wavelength interval and the radiation angle, θ, varied from 0° to 12°. Generally, the complex-coupled organic DFB laser facilitates single mode yield by removing the mode degeneracy that exists in pure index coupled or pure gain coupled DFB lasers [20][21][22]. From ...
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... photonic band diagram of the fabricated device was measured by illuminating with collimated white light and measuring the transmitted spectrum with a spectrometer (HR 4000, Ocean Optics) as a function of the incident angle. The consequent band diagram is shown in Fig. 2 (b), which agrees well with the simulated band diagram shown in Fig. 2 (a). Fig. 1. (b), measured photonic dispersion of the resonant modes. The experimentally obtained data suggests that the pumping light at λ = 532 nm couples to the resonant mode by following the photonic dispersion. Fig. 3. Near-field intensity calculation. Electric field intensity profile calculated using RCWA for the TE pumping mode at λ = 532 nm ...
Citations
... Hence, the lasing operation can be readily extended to other wavelength ranges. Such dual resonances can also be utilized with other types of gain materials, including organic semiconductor thin films 30 . In conclusion, with our successful demonstration of practical emission powers and the potential for wafer-scale production, we anticipate that our research will open up new opportunities for the implementation of semiconductor light sources on heterogeneous substrates, such as flexible substrates/wearables. Additionally, our work holds promise for the advancement of biological and chemical sensing, as well as quantum optics, information, and other technology platforms. ...
Semiconducting transition metal dichalcogenides (TMDs) have gained significant attention as a gain medium for nanolasers, owing to their unique ability to be easily placed and stacked on virtually any substrate. However, the atomically thin nature of the active material in existing TMD nanolasers presents a challenge, as their limited output power makes it difficult to distinguish between true laser operation and other "laser-like" phenomena. Here, we present comprehensive evidence of lasing from a CVD-grown tungsten disulphide (WS 2 ) monolayer. The monolayer is placed on a dual-resonance dielectric metasurface with a rectangular lattice designed to enhance both absorption and emission; resulting in an ultralow threshold operation (threshold <1 W/cm ² ). We provide a thorough study of the laser performance at room temperature, paying special attention to directionality, output power, and spatial coherence. Notably, our lasers demonstrated a coherence length of over 30 μm, which is several times greater than what has been reported for 2D material lasers so far. Our realisation of a single-mode laser from a wafer-scale CVD-grown monolayer presents exciting opportunities for integration and the development of novel applications.
... Spectrally and angle-resolved Fourier-plane measurements of the fabricated devices reveal an X-shaped pattern of photonic bands, typical of 2nd-order DFB resonators (Figure 6a, bottom). [39] It results from the 1st-order nearnormal Bragg scattering of two waves propagating in opposite directions in the plane of the DFB grating. The coupling between these waves, required for the lasing action, manifests as a sizable "stopband" (Δ sb = 4 nm or 13 meV) near ≈617 nm, which separates the higher-and lower-energy branches of the photon dispersion curve. ...
Laser diodes based on solution‐processable materials could benefit numerous technologies including integrated electronics and photonics, telecommunication, and medical diagnostics. An attractive system for implementing these devices is colloidal semiconductor quantum dots (QDs). The progress towards a QD laser diode has been hampered by fast nonradiative Auger decay of optical‐gain‐active multicarrier states, fast device degradation under high current densities required for laser action, and unfavorable competition between optical gain and optical losses in a multicomponent device stack. Here we resolve some of these challenges and demonstration optically excited lasing from a fully functional high‐current density electroluminescent (EL) devices with an integrated optical resonator. This advance has become possible due to excellent optical gain properties of compact, continuously graded QDs and a refined device architecture, which allows for highly efficient light amplification in a thin, EL‐active QD layer. This article is protected by copyright. All rights reserved
... Guided-mode resonance (GMR) supported by dielectric gratings has been used to enhance light-matter interactions [13][14][15][16][17]. In the design of low-threshold lasers, resonant optical pumping (ROP) based on the GMR effect has been proposed [18]. The ROP couples the pump light into the resonant mode using the same pump wavelength as the specific resonance wavelength, which results in an enhanced near-field and further pump absorption of the gain medium. ...
... The external excitation of the GMR mode with the same wavelength as the absorption peak of R6G and the pumping wavelength leads to the formation of high-intensity near fields that efficiently excite dye molecules. The above is the ROP technique that is commonly used in photonic crystal nanocavities [18]. Additionally, the quasi-BICs mode has a high Q-factor at resonance, which is beneficial for lasing behavior. ...
In this study, hybrid resonance modes are obtained when symmetry-breaking is introduced into a guided-mode resonance (GMR) grating, which transforms bound states in the continuum (BICs) into quasi-BICs with a high-quality factor while retaining the intrinsic GMR mode. The structural parameters are modified such that GMR and quasi-BICs resonance occur at the pump and emission wavelengths of the gain medium, respectively. Resonant optical pumping and high-quality nanocavities are utilized simultaneously, and a low-threshold laser is realized. We theoretically demonstrate that the threshold can be reduced to 24.6 µJ/cm², which is approximately 4 times lower than that of the laser based on GMR alone. The lasing action can be modulated by optimizing the asymmetry parameter and the electric field, and the threshold can be further reduced.
... Resolving the master equation is a very difficult task, thus in order to understand the DFB modes, the simulation by using the transfer matrix methods in periodic multilayered structures can be performed [16,17]. The information obtained from the eigenmodes is essential for better applications in laser diodes based on the conventional III-V semiconductor compounds [7,18,19] or on the novel hybrid organic-inorganic semiconductors [20e25], as well as in light-matter coupling phenomena [26]. ...
In this paper, one-dimensional photonic crystal distributed feedback structures were chosen for simulating the photonic modes. The corresponding photonic bands were calculated by using a numerical method for solving the master equation, while the reflectivity spectra of the structures were simulated by using a rigorous coupled wave analysis method. By observing the variation of the photonic band diagram and the reflectivity spectrum versus different geometrical parameters, the variation of the photonic bands was detailedly studied. We observed two kinds of photonic modes: (i) the one related to the vertical structures, and (ii) the other related to the horizontal periodic structures. The detailed analysis of the optical modes was illustrated by proposing TEn,X±,mBZ for indexing all transverse electric modes. An active layer coated on the distributed feedback structures plays an essential role in having radiative non-leaky photonic modes. The coupling between these modes, giving to anti-crossing, was also identified both by simulation and by modelling. This study can pave a way for further modelling optical modes in distributed feedback structures, and for selecting a suitable one-dimensional photonic crystal for optoelectronic applications with a specific active semiconductor layer.
... DFB cavities can be constructed by many approaches, such as interference lithography [44], nanoimprint lithography [151][152][153], photolithography [154], holographic interference [155][156][157], interference ablation [158,159], interference crosslinking [160,161], soft lithography [162], micromolding [147,163,164], electron beam lithography [165], and reactive ion etching [39]. ...
Considerable research efforts have been devoted to the investigation of distributed feedback (DFB) organic lasing in photonic crystals in recent decades. It is still a big challenge to realize DFB lasing in complex photonic crystals. This review discusses the recent progress on the DFB organic laser based on one-, two-, and three-dimensional photonic crystals. The photophysics of gain materials and the fabrication of laser cavities are also introduced. At last, future development trends of the lasers are prospected.
... Although the phase contrast of polymer structures is relatively small ( n Ä 0:04), the resulting group velocity anomaly provides a significant increase in the local field in such structures. Therefore, 2D structures are most widely studied as effective cavities for lasers with distributed feedback (DFB) [1][2][3][4][5][6][7][8][9][10][11][12]. Moreover, in comparison with 1D cavities, the use of 2D structures with the same contrast can increase the selectivity of the resonator, reduce the oscillation threshold, and improve the differential efficiency of DFB laser. ...
Two-dimensional (2D) photonic crystals formed by ordering of nanoparticles (NPs) of different nature in the polymeric matrix were studied. For 2D structure fabrication, we used a modified method of holographic lithography. Interfering beams (3, 4, 6) were formed using a spatial light modulator that provides a continuous phase shift between recording beams, variation of the structure symmetries as well as localization of polymer- and NP-enriched areas. The use of 2D structures in narrow-band lasers with distributed feedback and low lasing excitation threshold was demonstrated.
... When transverse magnetic (TM)polarized light satisfies a resonance condition, the electromagnetic field generated by SP waves is strongly enhanced and confined in the vicinity of the metal surface as a nonradiative evanescent field. The ability to concentrate the electromagnetic energy on the localized nanoscale domain, often in combination with a metallic nanostructure, may offer unique opportunities in a variety of technology developments, such as near-field microscopy [2], fluorescence detection [3], photovoltaic solar cells [4], and plasmon-assisted excitation schemes [5]. More recently, serious efforts have been also made to achieve enhanced field intensity or efficient light transmission through plasmonic waveguides or plasmonic nanoantennas [6][7][8][9][10]. ...
An optical process by which transmission wavelengths can be divided selectively by changing a resonance condition of surface plasmons (SPs) is demonstrated. When white light is incident to an SP resonance substrate with a dielectric grating, SP waves are excited at resonance and transmitted into the air via diffraction by a large-area grating pattern fabricated by nanoimprint lithography. While only a limited range of certain wavelengths is allowed to transmit, the peak transmission wavelength can be tuned continuously in the visible band. We also show that multiple wavelengths are transmitted into different directions simultaneously by using a wedge-shaped white light.
... Since the first report of optically pumped lasing from polymers in the solid state [1][2][3], amplified spontaneous emission (ASE) and lasing action have been demonstrated from many organic materials [2][3][4][5]. To reduce ASE threshold and obtain optical amplification, many types of structures have been used, for example, asymmetric slab waveguide [2,6], onedimensional distributed feedback [7], two dimensional distributed feedback [8][9][10], microdisk [11], microdroplet [12], microring [13], and distributed bragg reflectors [11] and microgoblet [14]. For the asymmetric slab waveguide structure, the optical amplification generally occurs in the guided mode [2,6]. ...
We investigate the emission spectra from the edge of optically pumped waveguide. The waveguide is based on vacuum-deposited thin films of small molecular, 2,5,2',5'-tetrakis(2,2-diphenylvinyl)biphenyl (TDPVBi). Narrowed emissions are observed both at high (> 6 KW/cm2) and low (< 1 W/cm2) pump power sources, which are attributed to two different propagation modes in the asymmetric slab waveguides, guided mode and cutoff mode, respectively. The peak wavelengths of the guided mode appear at the maximum of the photoluminescence (PL) spectrum of the TDPVBi film. In contrast, both the peak wavelength and polarization of the cutoff mode are thickness dependent. The optical gains of the two modes are measured by the variable stripe length (VSL) method. The amplification with an exceptional low threshold for the cutoff mode has been demonstrated. Our results suggest that the cutoff mode is a promising route for the reduction of lasing threshold.
Semiconducting transition metal dichalcogenides (TMDs) have gained significant attention as a gain medium for nanolasers, owing to their unique ability to be easily placed and stacked on virtually any substrate. However, the atomically thin nature of the active material in existing TMD lasers and the limited size due to mechanical exfoliation presents a challenge, as their limited output power makes it difficult to distinguish between true laser operation and other “laser-like” phenomena. Here, we present room temperature lasing from a large-area tungsten disulfide (WS2) monolayer, grown by a wafer-scale chemical vapor deposition (CVD) technique. The monolayer is placed on a dual-resonance dielectric metasurface with a rectangular lattice designed to enhance both absorption and emission, resulting in an ultralow threshold operation (threshold well below 1 W/cm²). We provide a thorough study of the laser performance, paying special attention to directionality, output power, and spatial coherence. Notably, our lasers demonstrated a coherence length of over 30 μm, which is several times greater than what has been reported for 2D material lasers so far. Our realization of a single-mode laser from a CVD-grown monolayer presents exciting opportunities for integration and the development of real-world applications.
Semiconducting transition metal dichalcogenides (TMDs) have gained significant attention as a gain medium for nanolasers, owing to their unique ability to be easily placed and stacked on virtually any substrate. However, the atomically thin nature of the active material in existing TMD lasers and the limited size due to mechanical exfoliation presents a challenge, as their limited output power makes it difficult to distinguish between true laser operation and other "laser-like" phenomena. Here, we present room temperature lasing from a large-area tungsten disulphide (WS2) monolayer, grown by a wafer-scale chemical vapor deposition (CVD) technique. The monolayer is placed on a dual-resonance dielectric metasurface with a rectangular lattice designed to enhance both absorption and emission; resulting in an ultralow threshold operation (threshold well below 1 W/cm2). We provide a thorough study of the laser performance, paying special attention to directionality, output power, and spatial coherence. Notably, our lasers demonstrated a coherence length of over 30 μm, which is several times greater than what has been reported for 2D material lasers so far. Our realisation of a single-mode laser from a CVD-grown monolayer presents exciting opportunities for integration and the development of novel applications.
