Abstract:Realization of one-chip, ultra-large-area, coherent semiconductor lasers has been one of the ultimate goals of laser physics and photonics for decades. Surface-emitting lasers with two-dimensional photonic crystal resonators, referred to as photonic-crystal surface-emitting lasers (PCSELs), are expected to show promise for this purpose. However, neither the general conditions nor the concrete photonic crystal structures to realize 100-W-to-1-kW-class single-mode operation in PCSELs have yet to be clarified. He… Show more
“…Figure 1b shows the photonic band structure of a typical double-lattice photonic crystal with a given lattice constant. As detailed in our previous paper 16 , for a double-lattice photonic crystal which has reflection symmetry along the u -axis, the band-edge modes can be classified into the following two groups: (1) anti-symmetric modes (A, C), which have electric-field vectors that are anti-symmetric about the u -axis, and (2) symmetric modes (B, D), which have electric-field vectors that are symmetric about the u -axis. In conventional PCSELs with uniform lattice constants, a band-edge mode with the smallest radiation constant (mode A in this case) induces a two-dimensional standing-wave resonance spreading over the whole area of the current injection region, resulting in uniform coherent lasing.…”
Section: Resultsmentioning
confidence: 98%
“…The cross section of the structure is shown in the left panel, where the above graded photonic crystal is located near the active layer and is incorporated inside a p-n junction for current injection. For the photonic-crystal layer, we employ a double-lattice photonic crystal, in which two holes are shifted in the x and y directions by about one quarter of the lattice constant 15 , 16 (see Supplementary Note 1 for details). Fig.…”
Section: Resultsmentioning
confidence: 99%
“…1a . The distance between the holes of each pair and their filling factors were appropriately adjusted to achieve a moderate radiation constant of the lasing mode ( α v ~ 10 cm −1 ) and a large threshold margin between the fundamental mode and higher-order modes (Δ α v ~ 9 cm −1 ) 16 (see Supplementary Note 1 ). To introduce the band-edge frequency gradation, the lattice constant ( a ) inside the current injection region was gradually changed using three gradient parameters ( α 1 , α 2 , β ) while that in the surrounding region was fixed, as shown in Fig.…”
Ultrafast dynamics in nanophotonic materials is attracting increasing attention from the perspective of exploring new physics in fundamental science and expanding functionalities in various photonic devices. In general, such dynamics is induced by external stimuli such as optical pumping or voltage application, which becomes more difficult as the optical power to be controlled becomes larger owing to the increase in the energy required for the external control. Here, we demonstrate a concept of the self-evolving photonic crystal, where the spatial profile of the photonic band is dynamically changed through carrier-photon interactions only by injecting continuous uniform current. Based on this concept, we experimentally demonstrate short-pulse generation with a high peak power of 80 W and a pulse width of <30 ps in a 1-mm-diameter GaAs-based photonic crystal. Our findings on self-evolving carrier-photon dynamics will greatly expand the potential of nanophotonic materials and will open up various scientific and industrial applications.
“…Figure 1b shows the photonic band structure of a typical double-lattice photonic crystal with a given lattice constant. As detailed in our previous paper 16 , for a double-lattice photonic crystal which has reflection symmetry along the u -axis, the band-edge modes can be classified into the following two groups: (1) anti-symmetric modes (A, C), which have electric-field vectors that are anti-symmetric about the u -axis, and (2) symmetric modes (B, D), which have electric-field vectors that are symmetric about the u -axis. In conventional PCSELs with uniform lattice constants, a band-edge mode with the smallest radiation constant (mode A in this case) induces a two-dimensional standing-wave resonance spreading over the whole area of the current injection region, resulting in uniform coherent lasing.…”
Section: Resultsmentioning
confidence: 98%
“…The cross section of the structure is shown in the left panel, where the above graded photonic crystal is located near the active layer and is incorporated inside a p-n junction for current injection. For the photonic-crystal layer, we employ a double-lattice photonic crystal, in which two holes are shifted in the x and y directions by about one quarter of the lattice constant 15 , 16 (see Supplementary Note 1 for details). Fig.…”
Section: Resultsmentioning
confidence: 99%
“…1a . The distance between the holes of each pair and their filling factors were appropriately adjusted to achieve a moderate radiation constant of the lasing mode ( α v ~ 10 cm −1 ) and a large threshold margin between the fundamental mode and higher-order modes (Δ α v ~ 9 cm −1 ) 16 (see Supplementary Note 1 ). To introduce the band-edge frequency gradation, the lattice constant ( a ) inside the current injection region was gradually changed using three gradient parameters ( α 1 , α 2 , β ) while that in the surrounding region was fixed, as shown in Fig.…”
Ultrafast dynamics in nanophotonic materials is attracting increasing attention from the perspective of exploring new physics in fundamental science and expanding functionalities in various photonic devices. In general, such dynamics is induced by external stimuli such as optical pumping or voltage application, which becomes more difficult as the optical power to be controlled becomes larger owing to the increase in the energy required for the external control. Here, we demonstrate a concept of the self-evolving photonic crystal, where the spatial profile of the photonic band is dynamically changed through carrier-photon interactions only by injecting continuous uniform current. Based on this concept, we experimentally demonstrate short-pulse generation with a high peak power of 80 W and a pulse width of <30 ps in a 1-mm-diameter GaAs-based photonic crystal. Our findings on self-evolving carrier-photon dynamics will greatly expand the potential of nanophotonic materials and will open up various scientific and industrial applications.
“…SE semiconductor lasers are important for a variety of fields such as photonics, information and communication technologies, and biomedical sciences 1 – 6 . Compared to edge-emitting lasers, SE lasers offer a number of advantages such as low beam divergence, circular far-field pattern, fast modulation speed, two-dimensional integration capability, and so on 5 , 7 .…”
Surface-emitting (SE) semiconductor lasers have changed our everyday life in various ways such as communication and sensing. Expanding the operation wavelength of SE semiconductor lasers to shorter ultraviolet (UV) wavelength range further broadens the applications to disinfection, medical diagnostics, phototherapy, and so on. Nonetheless, realizing SE lasers in the UV range has remained to be a challenge. Despite of the recent breakthrough in UV SE lasers with aluminum gallium nitride (AlGaN), the electrically injected AlGaN nanowire UV lasers are based on random optical cavities, whereas AlGaN UV vertical-cavity SE lasers (VCSELs) are all through optical pumping and are all with large lasing threshold power densities in the range of several hundred kW/cm2 to MW/cm2. Herein, we report ultralow threshold, SE lasing in the UV spectral range with GaN-based epitaxial nanowire photonic crystals. Lasing at 367 nm is measured, with a threshold of only around 7 kW/cm2 (~ 49 μJ/cm2), a factor of 100× reduction compared to the previously reported conventional AlGaN UV VCSELs at similar lasing wavelengths. This is also the first achievement of nanowire photonic crystal SE lasers in the UV range. Further given the excellent electrical doping that has already been established in III-nitride nanowires, this work offers a viable path for the development of the long-sought-after semiconductor UV SE lasers.
“…With these efforts, a 10-W peak power has been realized at room temperature on a single emitter until now. In a recent publication, Noda et al theoretically derived the conditions of a photonic crystal to maintain single mode operation as the device size increases above 3 mm [30]. However, other issues needed consideration in practice, such as nonuniform current distribution, self-heating, and stitching error from e-beam writing, which have not been addressed, and they may put some upper limit on device scaling.…”
Photonic crystal surface-emitting lasers (PCSELs) hold promising properties of both edge emitting lasers (EELs) and vertical-cavity surface-emitting lasers (VCSELs). They possess high output power while radiating light vertically, being thought of as the next generation laser source. One of the main advantages of PCSELs is their scalability of size and power, which makes them applicable to high power applications or long-distance detection. However, due to problems such as current injection and mode competition, there are limits on their dimensions. To further increase the power, the capability of two-dimensional array integration paves the way. In this work, we demonstrate a new method to fabricate PCSEL arrays by defining an isolation pattern. We also investigate the influence of aperture size and array arrangement on lasing performance.
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