Recent improvement in nitride lasers

Masui, Shingo; Nakatsu, Yoshitaka; Kasahara, Daiji; Nagahama, Shin–ichi

doi:10.1117/12.2247988

Cited by 40 publications

(30 citation statements)

References 4 publications

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“…Watt‐level blue and green LDs reported to date have been fabricated on conventional c‐plane GaN substrates . In general, c‐plane GaN has strong piezoelectric fields inside InGaN quantum wells with a high indium concentration.…”

Section: Polar and Semipolar Gan Substratesmentioning

confidence: 99%

“…These piezoelectric fields degrade the luminous efficiency through reduction of the recombination probability, so it has been difficult to fabricate green or longer‐wavelength light‐emitting devices on c‐plane GaN substrates. Although watt‐level output operation of green lasers at wavelengths of around 520 nm has been reported, their output powers and wall‐plug efficiencies decrease dramatically above 530 nm, the required wavelength to meet Rec. BT.2020 .…”

Section: Polar and Semipolar Gan Substratesmentioning

confidence: 99%

“…Although watt‐level output operation of green lasers at wavelengths of around 520 nm has been reported, their output powers and wall‐plug efficiencies decrease dramatically above 530 nm, the required wavelength to meet Rec. BT.2020 . In order to overcome this problem, it has been proposed to use nonpolar or semipolar GaN substrates for green lasers, in which there are no or smaller piezoelectric fields .…”

Section: Polar and Semipolar Gan Substratesmentioning

confidence: 99%

“…In particular, watt‐class LDs have been required for laser displays, such as business projectors, laser TVs, and large‐sized projection systems like those used in cinemas. GaN‐based lasers in the blue and green spectral ranges have been improved, and watt‐class output operations have been recently demonstrated . Although these blue lasers could operate with an output power of approximately 4 W at wavelengths of 445–455 nm, even longer wavelengths (467 nm) are needed to meet the ITU‐R Recommendation BT.2020 (hereinafter “Rec.…”

Section: Introductionmentioning

confidence: 99%

“…Watt‐level green lasers have been developed that are operable at a wavelength of 532 nm and that meet Rec. BT.2020 . However, their output powers are at most 1 W, which makes it difficult to satisfy the requirements for high‐luminescence laser displays.…”

Section: Introductionmentioning

confidence: 99%

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Watt‐Class Green (530 nm) and Blue (465 nm) Laser Diodes

Murayama¹,

Nakayama²,

Yamazaki³

et al. 2017

Physica Status Solidi (a)

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In this research, watt-class green and blue laser diodes, which are fabricated on free-standing semipolar 20 21g f GaN and conventional c-plane GaN substrates, respectively are developed. Although several research groups have recently developed green laser diodes on semipolar GaN substrates, which have weaker piezoelectric fields and higher indium homogeneity in InGaN active regions compared to c-plane GaN, watt-level output power has yet to be achieved. By utilizing the 20 21g f plane, the first watt-class green lasers at 530 nm is successfully fabricated, and achieve maximum output powers in excess of 2 W, which to the best of our knowledge is the highest value reported for any GaN-based green laser diode. A wall-plug efficiency of 17.5% is realized at a current of 1.2 A under continuous-wave operation, which corresponds to an optical output of approximately 1 W and is the highest value reported to date. In addition, high-power and high-efficiency blue laser diodes at 465 nm are successfully fabricated on conventional c-plane GaN substrates. The output power and wall-plug efficiency are 5.2 W and 37.0%, respectively, at a current of 3.0 A under continuous-wave operation. These laser diodes are promising light sources meeting the ITU-R Recommendation BT.2020 for future laser display applications.

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Section: Polar and Semipolar Gan Substratesmentioning

confidence: 99%

Section: Polar and Semipolar Gan Substratesmentioning

confidence: 99%

Section: Polar and Semipolar Gan Substratesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Watt‐Class Green (530 nm) and Blue (465 nm) Laser Diodes

Murayama¹,

Nakayama²,

Yamazaki³

et al. 2017

Physica Status Solidi (a)

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Laser‐Driven High‐Brightness Green Light for Underwater Wireless Optical Communication

Chen

Lin

Huang

et al. 2022

Advanced Optical Materials

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Green light is generally used as the transmitter of underwater wireless optical communication (UWOC) system, but the currently available light‐emitting diode (LED)‐based green light has a poor luminous flux density (i.e., low brightness) and a low wall‐plug efficiency (WPE), known as the “green gap”. In this work, it is proposed to produce the laser‐driven green light by using blue laser diodes to pump the narrow‐band green‐emitting β‐Sialon phosphor‐in‐glass (PiG) film. The dominant wavelength of the laser‐driven green light can be tuned in the range of ≈520–540 nm, required for UWOC, by controlling the phosphor content at ≈60–80% and the film thickness at ≈150–185 µm. By introducing highly reflective TiO2 into the PiG film, the laser‐driven green light exhibits a maximum luminous flux density of 1260 lm mm−2 under blue laser excitation with a power density of 15.49 W mm−2. For UWOC application, the green light is demonstrated to have a modulation bandwidth of 1.76 MHz, a high WPE of 8.7%, and a long transmission distance of ≈61.6 m. This work suggests that the laser‐driven high‐brightness green light will be a promising light source for UWOC.

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Color Conversion Materials for High‐Brightness Laser‐Driven Solid‐State Lighting

Wang

Hirosaki

et al. 2018

Laser & Photonics Reviews

293

191

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Solid‐state lighting is advancing toward higher power, higher brightness, and smaller size to cope with the market competitiveness, and laser‐driven solid‐state lighting technology is springing up owing to its super‐high brightness and compactness. These developments put forward new requirements for color conversion materials (i.e., phosphors). Here, the state‐of‐art achievements in laser phosphors are summarized, and the topics of luminescence saturation, light extraction efficiency, and light uniformity encountered in laser lighting technology are discussed. Several typical types of color converters, such as single crystal, phosphor ceramics, phosphor‐in‐glass, phosphor films, and quantum‐well light‐emitting diodes, are comparatively overviewed and discussed. The cutting‐edge applications of high‐brightness white laser light in lighting, displays, healthcare, and communications are summarized. The challenges and outlook in laser‐driven solid‐state lighting and some empirical rules for designing novel laser phosphors are highlighted.

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Recent improvement in nitride lasers

Cited by 40 publications

References 4 publications

Watt‐Class Green (530 nm) and Blue (465 nm) Laser Diodes

Watt‐Class Green (530 nm) and Blue (465 nm) Laser Diodes

Laser‐Driven High‐Brightness Green Light for Underwater Wireless Optical Communication

Color Conversion Materials for High‐Brightness Laser‐Driven Solid‐State Lighting

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