Chromium-doped forsterite as a solid-state saturable absorber

Demchuk, M. I.; Mikhailov, V. P.; Zhavoronkov, N.; Кулешов, Н. В.; Prokoshin, P. V.; Yumashev, K. V.; Livshits, M. G.; Minkov, B. I.

doi:10.1364/ol.17.000929

Cited by 69 publications

(17 citation statements)

References 5 publications

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“…Figure 7 shows the corresponding function T(θ). It can be seen that the degree of crystal bleaching for propagation of light along the [111] direction is less than for propagation along [100] for the same energy density of the incident radiation.…”

Section: Crmentioning

confidence: 97%

“…9a), where the linearly polarized radiation is propagated along one of the crystallographic axes (e.g., [100] [100] (1) and [111] (2) directions for energy flux density F 0 /F a = 30. because it interacts only with one set of dipoles. Two sets of dipoles interact with the radiation if the angle between the plane of polarization of the incident radiation and the crystallographic axes is different from zero.…”

Section: Crmentioning

confidence: 99%

“…Absorption bands for approximate C s symmetry from the ground state at 0.57 (E a), 0.66 (E c), and 0.74 μm (E b) are due to allowed transitions from the ground state [142]. The time for restoring the initial absorption is determined by the lifetime of the lower excited state [141] and is τ ≈ 2.7 μsec [25,99,100]. Bleaching is observed in Cr 4+ :Mg 2 SiO 4 crystal for radiation polarization E b and E c in the whole range of the corresponding bands of saturated absorption for λ ≈ 0.74 μm (E b) and λ ≈ 0.66 μm (E c) [60,142].…”

Section: Crmentioning

confidence: 99%

“…It was shown that the energy of a single pulse changes more than twice if the relative orientation of the polarization vector of the intracavity radiation and the crystallographic axes of Cr 4+ :Y 3 Al 5 O 12 crystal are changed. The pulse energy is highest when the polarization vector is parallel to the [100] crystallographic axis of the crystal (radiation is propagated along the other axis of the same type), i.e., when the PS has the lowest absorption saturation intensity (see Section 4.1). The lowest pulse energy is recorded when the polarization is parallel to the [110] direction in the crystal [196][197][198], which corresponds to the greatest value of I a of the PS.…”

Section: Ndmentioning

confidence: 99%

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Saturable absorbers based on tetrahedrally coordinated transition-metal ions in crystals (Review)

Malyarevich

Yumashev

2009

J Appl Spectrosc

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Published data on spectroscopic characteristics of saturable absorbers based on crystals doped with tetrahedrally coordinated transition-metal ions (Cr 2+ , Cr 4+ , Cr 5+ , V 3+ , Cr 2+ , Fe 2+ ) in addition to their use as passive Q-switches for solid-state lasers emitting in the visible and near-infrared regions are reviewed.Introduction. The use of saturable absorbers (SA) as passive Q-switches (PS) in solid-state lasers is an effective method for generating nanosecond and subnanosecond light pulses. This method differs favorably from active control of laser cavity gain by the lack of mechanical perturbations of the optical devices, additional sources of power supply, and external electrical control circuits. This simplifies the construction and operation of the laser and reduces its cost. Compact solid-state mini-lasers and ultra-small lasers (so-called microchip lasers) can be fabricated if PS are used.A SA is an optical material for which the transmission increases with increasing power density of the incident radiation. The SA should satisfy several requirements in order to be used as a PS. First of all this applies to SA characteristics at the laser operating wavelength such as absorption saturation energy density, coefficient of residual absorption in the fully bleached state, bleaching rise and fall time, and optical destruction threshold. The requirements for their absolute values depend on the spectroscopic properties of the lasing medium (LM) and the laser cavity parameters.In most instances with certain exceptions, SA based on tetrahedrally coordinated (TC) transition-metal ions of the iron group have bleaching relaxation times that are longer than the generation time of the laser pulses obtained using them. Such SA are usually called slowly relaxing. Relaxation processes leading to a restoration of their initial absorption can be ignored in analyzing their operation in a laser. In the simplest instance (if a four-level diagram is used for the spectroscopic model of the SA), the criterion for SA functioning as a PS is written [1-8]:

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Section: Crmentioning

confidence: 97%

Section: Crmentioning

confidence: 99%

Section: Crmentioning

confidence: 99%

Section: Ndmentioning

confidence: 99%

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Saturable absorbers based on tetrahedrally coordinated transition-metal ions in crystals (Review)

Malyarevich

Yumashev

2009

J Appl Spectrosc

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“…4 ' 5 Cr-doped forsterite has been used to realize passive Q switching and mode locking in Nd:YAG lasers. 2 When YAG and gadolinium scandium gallium garnet host crystals are codoped with Nd and Cr, the functions of the gain medium and the saturable absorber are combined. This result has led to self-Q-switched operation.…”

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confidence: 99%

Monolithic self-Q-switched Cr,Nd:YAG laser

et al. 1993

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We report the operation of a diode-pumped monolithic self-Q-switched Cr,Nd:YAG laser in which the codoped ions create saturable absorption for Nd 3 " laser emission at 1064 nm. With a 70-/um beam diameter in the gain medium, the Q-switched pulse has a duration of 3.5 ns and a peak power of 2 kW. The output is linearly polarized with an extinction ratio of 600:1. The pulse-to-pulse intensity fluctuation is less than the instrument resolution of 0.25%. A 5-mm-long KTP crystal butted against the with a peak power-conversion efficiency of 30%.Recently, chromium-doped host crystals, such as gadolinium scandium gallium garnet, forsterite, and yttrium aluminum garnet (YAG) were found to exhibit saturable absorption in the 900-1200-nm range.`3 The absorption has color-centerlike characteristics and is believed to be associated with the Cr 4 " ions. 4 ' 5 Cr-doped forsterite has been used to realize passive Q switching and mode locking in Nd:YAG lasers. 2When YAG and gadolinium scandium gallium garnet host crystals are codoped with Nd and Cr, the functions of the gain medium and the saturable absorber are combined. This result has led to self-Q-switched operation."3 The output of the Cr,Nd:YAG crystal is linearly polarized without any polarizing optics in the cavity. 3 In this Letter we report the operation of a diodepumped monolithic self-Q-switched solid-state laser that is based on Cr,Nd:YAG. Our purpose is to demonstrate a compact, efficient, highly polarized, and highly stable Q-switched laser. The applications of Q-switched lasers are well known: lidars, remote sensing, pollution detection, nonlinear-optical processes, and material processing. Pulse-to-pulse stability is also important for measurement accuracy.The device configuration is illustrated in Fig. 1. A Cr,Nd:YAG crystal is polished to a planar-concave geometry. The concave mirror has a radius of curvature of 80 mm and is coated for high transmission at 808 nm and total reflection at 1064 nm. The planar surface is coated for 95% reflection as the output coupler. The misalignment of the axes of the two mirrors is measured to be less than 0.3°. The absorption coefficient is measured to be 5.25 cm-' at the pumping wavelength of 808 nm, which is typical of a 1 wt. % Nd:YAG. Because both Cr 3 + and Cr 4 + are present in the absorption spectrum, 3 the concentration of the absorbers is not known, although absorption loss at 1064 nm is 0.32 cm-' at low power. The saturation power density at 1064 nm was measured previously to be 3.6 MW/cm 2 .3 Thus this absorption can easily be saturated with an monolithic cavity produces 2-ns-long pulses at 532 nm intracavity power of 100 W in a diode-end-pumped Nd:YAG laser if the spot diameter at the absorber is 50 /.m. With end pumping, the pumping power is mostly depleted within the 3-mm length in the front end of the crystal facing the pump source, and the saturable loss is evenly distributed throughout the length. A longer crystal is expected to result in shorter pulses and higher threshold. As a compromise between the avail...

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Local Chemistry Engineering in Doped Photonic Glass for Optical Pulse Generation

Chen

Shi

Zhou

et al. 2019

Advanced Optical Materials

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The control of the optical response of multicomponent photonic glass through short‐ to medium‐range chemistry design has led to the development of high‐performance devices with efficient stimulated radiation, broadband optical amplification, and sensitive optical sensing. However, the success of optical modulation with an all‐fiber configuration is limited by the difficulty in creating smart structural units that can dynamically switch light–matter interactions. Here, a local chemistry design strategy is reported that can help realize dynamic energy storage and its controllable release, based on the simultaneous management of the chemical state and ligand field of transition‐metal dopant through glass crystallization. The theoretical analysis indicates that a four‐level configuration, such as that of tetrahedral Cr4+, can enable efficient photon–electron–photon conversion. Experimental data further reveal that this configuration can be stable in nanostructured glass. A nanostructured fiber with perfect core‐clad configuration is successfully fabricated by the melt‐in‐tube approach. The optical modulation function in bulk glass with estimated σgs and σes values of (1.39 ± 0.03) × 10−16 and (1.20 ± 0.02) × 10−16 cm2, respectively, is also demonstrated. Therefore, a principle pulse laser device with operation wavelength at 1.06 µm and pulse duration of 176 ns is fabricated for the first time.

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Chromium-doped forsterite as a solid-state saturable absorber

Cited by 69 publications

References 5 publications

Saturable absorbers based on tetrahedrally coordinated transition-metal ions in crystals (Review)

Saturable absorbers based on tetrahedrally coordinated transition-metal ions in crystals (Review)

Monolithic self-Q-switched Cr,Nd:YAG laser

Local Chemistry Engineering in Doped Photonic Glass for Optical Pulse Generation

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