Erbium-doped and Raman microlasers on a silicon chip fabricated by the sol–gel process

Yang, Lan; Carmon, Tal; Min, Bumki; Spillane, S. M.; Vahala, Kerry J.

doi:10.1063/1.1873043

Cited by 148 publications

(119 citation statements)

References 15 publications

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“…24 Furthermore; the homogeneity of the distribution of Yb 3+ is another necessary condition which optimizes the overlap between pump modes and WGMs, which also results in the low threshold. 25 With the increase of excitation power, short-wavelength shift CL around 468 nm is also observed, means the peak wavelength 20 nm short-wavelength shift than the two photons absorption emission of 488 nm. The luminescence is intense enough that could easily be seen by naked eyes, even if the excitation power is only 5.29 μW.…”

Section: Resultsmentioning

confidence: 96%

Ultralow-threshold laser and blue shift cooperative luminescence in a Yb3+ doped silica microsphere

Huang

Zhang

et al. 2014

AIP Advances

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An experimental investigation on ultralow threshold laser and blue shift cooperative luminescence (CL) in a Yb3+ doped silica microsphere (YDSM) with continuous-wave 976 nm laser diode pumping is reported. The experimental results show that the YDSM emits laser oscillation with ultralow threshold of 2.62 μW, and the laser spectrum is modulated by the microsphere morphology characteristics. In addition, blue emission of YDSM is also observed with the increase of pump power, which is supposed to be generated by CL of excited Yb ion-pairs with the absorption of 976 nm photons and Si-O vibration phonons, and the process is explained with an energy level diagram. This property of the blue shift CL with phonons absorption in the Yb3+doped microcavity makes it attractive for the application of laser cooling based on anti-Stokes fluorescence emission, if the Yb3+doped microcavity made from with low phonon energy host materials.

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Section: Resultsmentioning

confidence: 96%

Ultralow-threshold laser and blue shift cooperative luminescence in a Yb3+ doped silica microsphere

Huang

Zhang

et al. 2014

AIP Advances

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“…Recently, the ultrahigh-Q ͑Ͼ10 8 ͒ toroid whispering-gallery resonator was invented [4]. The extremely low loss of this device enabled significant reduction of the threshold for an Erdoped silica solgel laser [5]. The Yb silica toroid microcavity laser reported in this Letter has an onresonance finesse greater than 10,000.…”

mentioning

confidence: 89%

“…The microtoroid laser cavity FSR is 6 nm. It is also possible to excite modes that experience pulsations in the laser output power similar to those found in an Er 3+ : SiO 2 microtoroid laser [5]. Pulsing is most easily observed for higher doping concentration (typically 2 ϫ 10 19 cm −3 ), and pulsing with 1 MHz repetition rate and 200 ns duration was measured.…”

mentioning

confidence: 91%

Ultralow-threshold Yb^3+:SiO_2 glass laser fabricated by the solgel process

2007

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A Yb-doped silica microcavity laser on a silicon chip is fabricated from a solgel thin film. The high-Q microtoroid cavity, which has a finesse of 10,000, is evanescently coupled to an optical fiber taper. We report a threshold of 1.8 W absorbed power that is, to the best of our knowledge, the lowest published threshold to date for any Yb-doped laser. . In addition, the rare-earth aggregate emission spectrum spans many key wavelengths from 0.3 to 3 m that are important for imaging, sensing, medical treatment, and communications. While rareearth lasers have been built in large form factors for high-power laser cutting and defense applications, they can also be designed to be small, low power, and ultrasensitive to the environment. The laser resonator finesse, defined as the free spectral range (FSR) divided by the resonance linewidth, quantifies the loss and hence energy storage efficiency of a resonator. For a given cavity, higher finesse results in lower threshold for lasing. Lacovara et al. measured a 71 mW threshold for a Yb 3+

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“…Finally, to investigate the emission property of the deformed microcavities, we fabricated erbium-doped silica deformed microtoroids [ 34 ] with the Er 3 + ions concentration of 2 × 10 19 cm − 3 . The gain medium in the microcavities may be effi ciently excited using a free-space vertical focused laser beam [ 35 , 36 ] where the pump laser is typically nonresonant with the cavity mode.…”

Section: C) As Shown Inmentioning

confidence: 99%

Highly Unidirectional Emission and Ultralow‐Threshold Lasing from On‐Chip Ultrahigh‐Q Microcavities

et al. 2012

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Confi nement and manipulation of photons using microcavities have triggered intense research interest for more than a decade. [ 1 ] Prominent examples are whispering gallery mode (WGM) microcavities, [ 2 , 3 ] which confi ne photons by means of continuous total internal refl ection along a curved and smooth surface. The long photon lifetime (described by high Q factors), strong fi eld confi nement, and in-plane emission characteristics make them promising candidates for novel light sources [4][5][6][7][8][9] and biochemical sensors with the ability of detecting few or even single nanoparticles. [ 10 , 11 ] The principal disadvantage of circular WGM microcavities is their intrinsic isotropy of emission due to their rotational symmetry. In addition to the photonic structures consisting of two or more perfectly spherical microcavities, [ 12 ] one of vital solutions is to use deformed microcavities by breaking the rotational symmetry, [13][14][15][16] which can provide not only the directional emission but also the effi cient and robust excitation of WGMs by a free-space optical beam. [17][18][19][20] Deformed microcavities fabricated on a chip are particularly desired for high-density optoelectronic integration, but they suffer from low Q factors in experiments. The Q factors are typically around or even smaller than ten thousand [21][22][23][24][25][26][27] limited by the large scattering losses from the involuntary surface roughness. The high Q factor is of great importance in fundamental studies and on-chip photonic applications. Here, with a pattern transfer technique and a refl ow process ensuring a nearly atomic-scale microcavity surface, we demonstrate experimentally on-chip undoped silica deformed microcavities which support both nearly unidirectional emission and ultrahigh Q factors exceeding 100 million. Consequently, low-threshold, unidirectional microlasing in such a microcavity with Q factor about 3 million is realized by erbium doping and a convenient free-space excitation.The deformed microcavities are fabricated from a 2-μ mthick layer of silicon dioxide on a silicon wafer. Combining a two-step dry etching process and a laser refl ow process is employed for the fi rst time to transfer patterns and achieve microcavities with designed shapes and ultra-smooth cavity surface. The process details are depicted in Figure 1 a. First, we purposely design the mask patterns with minor modifications from the desired deformed toroidal boundaries R ( ϕ ) by adding an extra 15 μ m in the radius at all polar angles. Through optical lithography followed by buffered HF etching, deformed silica disks are created on the silicon wafer, which inherit the mask patterns well. Subsequently, the resulting silica disks are exposed to XeF 2 gas at 2.7 torr to etch the underneath silicon by about 15 μ m. In this process, the silica disks keep their original shapes and also serve as etching masks for the silicon underneath; consequently a silicon pillar is formed under each disk. Owing to the isotropic dry etching of silicon, ...

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Erbium-doped and Raman microlasers on a silicon chip fabricated by the sol–gel process

Cited by 148 publications

References 15 publications

Ultralow-threshold laser and blue shift cooperative luminescence in a Yb3+ doped silica microsphere

Ultralow-threshold laser and blue shift cooperative luminescence in a Yb3+ doped silica microsphere

Ultralow-threshold Yb^3+:SiO_2 glass laser fabricated by the solgel process

Highly Unidirectional Emission and Ultralow‐Threshold Lasing from On‐Chip Ultrahigh‐Q Microcavities

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