CN105063755B - The mesosilicate crystal of activated by erbium ions and its 1.55 micron waveband Solid Laser Elements - Google Patents

Abstract

The mesosilicate crystal of activated by erbium ions and its 1.55 micron waveband Solid Laser Elements, are related to laser crystal and devices field.The molecular formula of the crystalloid is：(Er_xYb_yRe_(1‑x‑y))₂Si₂O₇Or (Er_xYb_1‑x)₂Si₂O₇, wherein x=0.002 0.02, y=0.05 0.5, the combination of a certain element or some elements in Re Y, Gd, Lu element.Using this crystalloid as gain media, using the semiconductor laser pumping of wave band near 976nm, high performance 1.55 mu m waveband Solid State Laser output can be achieved.

Description

Erbium ion activated pyrosilicate crystal and its 1.55 micron band solid-state laser device

technical field

The invention relates to the field of laser crystals and devices.

Background technique

The 1.55μm band laser obtained by using the erbium ion ⁴ I _13/2 → ⁴ I _15/2 transition is in the window of optical fiber communication and atmospheric transmission, and is safe for human eyes, and can be widely used in national defense and civilian fields. A technical approach to obtain lasers in this band is to use Yb ³⁺ which has a large absorption cross section for semiconductor lasers near 976nm as sensitized ions, and make Er ³⁺ settle on the ⁴ I _11/2 energy level through energy transfer. Then through the non ^- radiative relaxation of ⁴ I _11/2 ^{→ 4} I _13/2 , the _upper energy level ⁴ I _13/2 of the laser is effectively _populated , and finally the 1.55 Laser output in the μm band.

Pyrosilicate crystal has stable physical and chemical properties, high hardness and good thermal performance. Erbium ions have a short ⁴ I _11/2 energy level fluorescence lifetime (about 9 μs) in this type of crystal, so most of the particles on the pump energy level can settle to the upper laser energy level through fast non-radiative relaxation , to achieve efficient operation of the 1.55μm band laser. At the same time, the longer ⁴ I _13/2 energy level fluorescence lifetime (about 9ms) is also beneficial to the energy storage of the upper energy level of the Er ³⁺ laser, reducing the heat generation of the crystal caused by non-radiative relaxation, and reducing the thermal effect of the laser crystal.

Contents of the invention

The purpose of the present invention is to provide a kind of pyrosilicate laser crystal activated by erbium ions, and use this kind of crystal as a gain medium to obtain a 1.55 μm band solid laser with high efficiency and high average output power.

The present invention includes following technical solutions:

1. A class of pyrosilicate laser crystals activated by erbium ions. The molecular formula of this kind of crystal is: (Er _x Yb _y Re _(1-xy) ) ₂ Si ₂ O ₇ or (Er _x Yb _1-x ) ₂ Si ₂ O ₇ , where x=0.002-0.02, y=0.05- 0.5, Re is a certain element or a combination of several elements among Y, Gd, and Lu elements.

2. A 1.55 μm band solid-state laser is made up of a semiconductor laser pumping system, a laser resonator and a gain medium, and is characterized in that: the crystal as described in item 1 is used as the gain medium of the laser; the semiconductor laser pumping system includes Semiconductor laser with a wavelength near 976nm and an optical coupler placed between the semiconductor laser and the gain medium; the laser resonator is composed of input and output mirrors; the input mirror is designed to have a wavelength transmittance T≥70% near 976nm, and in the 1.55μm band Transmittance T≤1%; the output mirror is designed to have a transmittance of 0.5%≤T≤10% in the 1.55μm band.

3. The solid-state laser as described in Item 2, characterized in that: the input and output mirrors are respectively directly plated on one or two opposite end faces of the gain medium.

4. A 1.55 μm band solid-state pulsed laser, characterized in that: a Q-switching or mode-locking element of the 1.55 μm band is inserted between the gain medium and the output mirror of the laser described in item 2; The components are simultaneously placed in the laser cavity.

5. The solid-state laser as described in item 4 is characterized in that: the input mirror is directly plated on the input end face of the gain medium; the output mirror can also be directly plated on the output of the described Q-switching or mode-locking element end face.

6. A tunable solid-state laser in the 1.55 μm band, characterized in that: a wavelength tuning element in the 1.55 μm band is inserted between the gain medium and the output mirror of the laser described in item 2.

7. A 1.55 μm band frequency doubling laser, characterized in that: a frequency doubling crystal of the 1.55 μm band is inserted between the gain medium and the output mirror of the laser described in item 2, and the laser resonator output mirror is designed to be in the 1.55 μm band The transmittance at the frequency doubling band is less than 0.5%, and the transmittance at the frequency doubling band is greater than 80%. The output mirror can also be directly plated on the output end surface of the frequency doubling crystal.

The beneficial effects of implementing the technical solution of the present invention are: using (Er _x Yb _y Re _(1-xy) ) ₂ Si ₂ O ₇ or (Er _x Yb _1-x ) ₂ Si ₂ O ₇ crystals as the gain medium, can obtain High output power and high efficiency CW and high pulse energy, high repetition frequency and narrow pulse width Q-switched pulse 1.55μm band solid-state laser.

detailed description

Example 1: 976nm semiconductor laser end-pumped Er:Yb:Lu ₂ Si ₂ O ₇ crystal to achieve 1.53μm solid-state laser output.

(Er _0.0025 Yb _0.1 Lu _0.8975 ) ₂ Si ₂ O ₇ laser crystals were grown by pulling method. The crystal belongs to the monoclinic crystal system and has three optical axes, which are X, Y, and Z respectively. After orientation with a polarizing microscope, take an XY slice, and cut the crystal with a thickness of 1 mm (end area is generally square millimeters to square centimeters) according to the absorption rate of 80% because the absorption coefficient at 976 nm of the pump light is about 15 cm ^-1 The sample is fixed on a copper seat with a light hole in the middle after the end face is polished and placed in the laser cavity. The transmittance of the input mirror of the laser cavity is T=90% at the wavelength of 976nm, and the transmittance of T=0.1% at the wavelength of 1.53 μm; the transmittance of the output mirror of the laser cavity is T=3.5% at the wavelength of 1.53 μm. A 1.53μm solid-state laser output with a continuous power higher than 1.5W can be obtained by using a 10W 976nm semiconductor laser end-pump. The input and output mirrors of the laser cavity can also be directly plated on the two end faces of the laser crystal respectively to achieve the same purpose.

Example 2: 976nm semiconductor laser end-pumped Er:Yb:Lu ₂ Si ₂ O ₇ crystal to achieve 1.53μm solid-state pulsed laser output.

Directly insert a passive Q-switching chip (such as Co ²⁺ : MgAl ₂ O ₄ , Co ²⁺ : ZnSe, Cr ²⁺ : ZnSe, etc.) or an acousto-optic Q-switching module in the 1.53 μm band between the laser crystal and the output mirror in Example 1. 1.53μm Q-switched pulsed laser operation can be realized. The output mirror can also be directly plated on the output end surface of the passive Q-switching chip or the acousto-optic Q-switching module to achieve the same purpose.

Example 3: 976nm semiconductor laser end-pumped Er:Yb:Lu ₂ Si ₂ O ₇ crystal to realize 1520-1570nm tunable solid-state laser output.

The laser crystal sample in Example 1 was fixed on a copper seat with a light hole in the middle and placed in the laser cavity. The transmittance of the input mirror of the laser cavity is T=90% at the wavelength of 976nm, and the transmittance of T=0.1% at the wavelength of 1.5-1.6 μm; the transmittance of the output mirror of the laser cavity is T=1% at the wavelength of 1.5-1.6 μm. Insert the wavelength tuning element (birefringence filter, grating or prism, etc.) in the 1.55μm band between the laser crystal and the laser cavity output mirror, and use the 976nm semiconductor laser end pump to achieve 1520-1570nm tunable laser output.

Example 4: 976nm semiconductor laser end-pumped Er:Yb:Lu ₂ Si ₂ O ₇ crystal to achieve 810nm frequency-doubled solid-state laser output.

Directly insert the nonlinear optical crystal (such as KTP, LBO, β-BBO, etc.) of the frequency doubling 1620nm band between the laser crystal and the output mirror in Example 1. Coat the input mirror of the laser cavity with a dielectric film with transmittance T=90% at 976nm wavelength and high reflection (T≤0.5%) at 1620 and 810nm wavelength; coat the output mirror with high reflection at 1620nm wavelength (T≤0.5%) 0.5%), a high-transmittance (T≥80%) dielectric film at a frequency doubled wavelength of 810nm. With 976nm semiconductor laser pumping, 810nm frequency doubled laser output can be realized. The output mirror can also be directly plated on the output end surface of the nonlinear optical crystal to achieve the same purpose.

Example 5: 976nm semiconductor laser end-pumped Er:Yb:Gd ₂ Si ₂ O ₇ crystal to achieve 1.56μm solid-state laser output.

(Er _0.008 Yb _0.25 Gd _0.742 ) ₂ Si ₂ O ₇ laser crystals were grown by pulling method. The crystal belongs to the monoclinic crystal system and has three optical axes, which are X, Y, and Z respectively. After orientation with a polarizing microscope, take an XZ section, and cut the crystal with a thickness of 400 μm (end area is generally square millimeters to square centimeters) according to the absorption rate of 80% because the absorption coefficient at 976 nm of the pump light is about 40 cm ^-1 The sample is fixed on a copper seat with a light hole in the middle after the end face is polished and placed in the laser cavity. The transmittance of the input mirror of the laser cavity is T=90% at the wavelength of 976 nm, and the transmittance of T=0.1% at the wavelength of 1.56 μm; the transmittance of the output mirror of the laser cavity is T=2.0% at the wavelength of 1.56 μm. A 1.56μm solid-state laser output with a continuous power higher than 1.2W can be obtained by using a 10W 976nm semiconductor laser end pump. The input and output mirrors of the laser cavity can also be directly plated on the two end faces of the laser crystal respectively to achieve the same purpose.

Example 6: 976nm semiconductor laser end-pumped Er:Yb:Y ₂ Si ₂ O ₇ crystal to achieve 1.6μm solid-state laser output.

(Er _0.01 Yb _0.4 Y _0.59 ) ₂ Si ₂ O ₇ laser crystals were grown by pulling method. The crystal belongs to the monoclinic crystal system and has three optical axes, which are X, Y, and Z respectively. After orientation using a polarizing microscope, take an XY section, and since the absorption coefficient at 976 nm of the pump light is about 60 cm ^-1 , cut the crystal with a thickness of 250 μm (the end area is generally square millimeters to square centimeters) according to the absorption rate of 80% The sample is fixed on a copper seat with a light hole in the middle after the end face is polished and placed in the laser cavity. The transmittance of the input mirror of the laser cavity is T=90% at the wavelength of 976nm, and the transmittance of T=0.1% at the wavelength of 1.6 μm; the transmittance of the output mirror of the laser cavity is T=1.0% at the wavelength of 1.6 μm. A 1.6μm solid-state laser output with a continuous power higher than 0.7W can be obtained by using a 10W 976nm semiconductor laser end pump. The input and output mirrors of the laser cavity can also be directly plated on the two end faces of the laser crystal respectively to achieve the same purpose.

Example 7: 976nm semiconductor laser end-pumped Er:Yb ₂ Si ₂ O ₇ crystal to achieve 1.54μm solid-state laser output.

(Er _0.015 Yb _0.985 ) ₂ Si ₂ O ₇ laser crystals were grown by pulling method. After orientation with a polarizing microscope, take an XY section, and cut the crystal with a thickness of 100 μm (end area is generally square millimeters to square centimeters) according to the absorption rate of 80% because the absorption coefficient at 976 nm of the pump light is about 160 cm ^-1 The sample is fixed on a copper seat with a light hole in the middle after the end face is polished and placed in the laser cavity. The transmittance of the input mirror of the laser cavity is T=90% at the wavelength of 976nm, and the transmittance of T=0.1% at the wavelength of 1.54μm; the transmittance of the output mirror of the laser cavity is T=2.5% at the wavelength of 1.54μm. A 1.54μm solid-state laser output with a continuous power higher than 1.0W can be obtained by using a 10W 976nm semiconductor laser end pump. The input and output mirrors of the laser cavity can also be directly plated on the two end faces of the laser crystal respectively to achieve the same purpose.

Claims (9)

1. A class of 1.55μm band lasers uses erbium ions to activate pyrosilicate crystals. The molecular formula of this type of crystals is: (Er _x Yb _y Re _(1-xy) ) ₂ Si ₂ O ₇ , where x=0.002-0.02, y=0.05-0.5, Re is an element or a combination of several elements among Y, Gd, and Lu; or, its molecular formula is: (Er _x Yb _1-x ) ₂ Si ₂ O ₇ , where x=0.002-0.015 . 2. A 1.55 μm band solid-state laser is made up of a semiconductor laser pumping system, a laser resonator and a gain medium, and is characterized in that: a class of 1.55 μm band laser uses erbium ions to activate pyrosilicate crystals as the gain of the laser Medium, the molecular formula of this type of crystal is: (Er _x Yb _y Re _(1-xy) ) ₂ Si ₂ O ₇ or (Er _x Yb _1-x ) ₂ Si ₂ O ₇ , where x=0.002-0.02, y= 0.05-0.5, Re is a certain element or a combination of several elements among Y, Gd, and Lu elements; the semiconductor laser pumping system includes a semiconductor laser with a wavelength near 976nm and an optical coupler placed between the semiconductor laser and the gain medium; laser resonance The cavity is composed of input and output mirrors; the input mirror is designed to have a transmittance T≥70% near the wavelength of 976nm, and the transmittance T≤1% at the 1.55μm band; the output mirror is designed to have a transmittance of 0.5 at the 1.55μm band %≤T≤10%. 3. The solid-state laser according to claim 2, wherein the input and output mirrors are respectively directly plated on one or two opposite end faces of the gain medium. 4. A 1.55 μm band solid-state pulsed laser, characterized in that: between the gain medium of the laser described in claim 2 and the output mirror, Q-switching or mode-locking elements of the 1.55 μm band are inserted; or, Q-switching and locking The mode element is placed in the laser cavity at the same time. 5. The solid-state pulsed laser according to claim 4, wherein the input mirror is directly plated on the input end surface of the gain medium. 6. The solid-state pulsed laser according to claim 4 or 5, characterized in that the output mirror is directly plated on the output end face of the Q-switching or mode-locking element. 7. A tunable solid-state laser in the 1.55 μm band, characterized in that: a wavelength tuning element in the 1.55 μm band is inserted between the gain medium and the output mirror of the laser according to claim 2. 8. A 1.55 μm band frequency doubling laser, characterized in that: a frequency doubling crystal of the 1.55 μm band is inserted between the gain medium and the output mirror of the laser according to claim 2, and the output mirror of the laser resonator is designed to be at 1.55 μm The transmittance at the band is less than 0.5%, and the transmittance at the octave band is greater than 80%. 9. The frequency doubling laser according to claim 8, wherein the output mirror is directly plated on the output end surface of the frequency doubling crystal.