Cr:YAG Passive Q-Switch Crystals
ATR Crystal supplies Cr:YAG (Cr4+:YAG) passive Q-switch crystals for 1064 nm laser systems. Initial transmission, dimensions, surface finish and coating requirements can be reviewed against your drawing or specification. For a quotation, send your target initial transmission at the operating wavelength, dimensions, coating requirements and quantity. If some details are still undecided, send the specifications you already have so we can identify what needs to be confirmed.
Built around your specification
- Dimensions
- Diameter or square aperture, thickness, clear aperture, chamfer, and drawing if available.
- Anti-reflection coating
- R < 0.15% at 1064 nm per surface
Final specifications and acceptance criteria are confirmed for the quoted configuration.
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Cr:YAG Passive Q-Switch Crystal for Compact Pulsed Lasers
Cr:YAG passive Q-switch crystal, also written as Cr4+:YAG or chromium-doped YAG, is a solid-state saturable absorber used for passive Q-switching of Nd and Yb doped laser systems. It is commonly selected for compact pulsed lasers where a simple, stable, and small-footprint Q-switch solution is preferred over an electro-optic driver or acousto-optic modulator.
Cr:YAG is widely used with Nd:YAG, Nd:YVO4, Nd:YLF, and Yb:YAG laser cavities operating in the near-infrared region. By selecting the proper initial transmittance, absorption coefficient, aperture, thickness, coating, and optical quality, the crystal helps generate high peak-power pulses in a compact laser design.
ATR Crystal supplies Cr:YAG passive Q-switch crystals with custom dimensions, orientation, initial transmittance, polishing, AR coating, and inspection requirements. For related laser materials, review our laser crystal category, Nd:YAG crystal, Yb:YAG crystal, Nd:YVO4 crystal, and Er:YAG crystal.
Cr:YAG is a passive Q-switch crystal rather than the main gain medium. It is commonly reviewed together with Nd:YAG, Nd:YVO4 or Yb:YAG when a compact pulsed laser design needs fewer active switching components. See the laser crystal selection guide for the full material comparison.
Advantages of Cr:YAG Laser Crystal
- Passive Q-switching Cr:YAG works as a saturable absorber and can generate pulsed output without high-voltage electro-optic drivers.
- Compact laser design Passive Q-switching helps reduce system size, wiring complexity, alignment burden, and component count.
- Nd and Yb laser compatibility Cr:YAG is commonly used with Nd:YAG, Nd:YVO4, Nd:YLF, Yb:YAG, and other near-infrared laser cavities.
- Selectable initial transmittance Initial transmittance can be selected according to cavity gain, pump level, pulse energy, repetition rate, and beam size.
- Stable YAG host The YAG host provides good mechanical hardness, chemical stability, thermal behavior, and high optical damage resistance.
- Custom aperture and coating Diameter, square aperture, thickness, AR coating, surface quality, and clear aperture can be specified for OEM designs.
How to Specify Cr:YAG Initial Transmission at 1064 nm
Cr:YAG initial transmission, also called initial transmittance or T0, describes transmission in the small-signal, unsaturated state at a specified wavelength. It is different from the transmission reached when the absorber is saturated during a laser pulse.
For a 1064 nm passive Q-switch, write the target as a percentage at 1064 nm rather than specifying only a chromium concentration or a crystal thickness. The listed 5%-95% range describes product options for review; the quoted transmission, tolerance and inspection basis must be confirmed for the requested part.
- Wavelength: State the actual laser wavelength. A transmission value at 1064 nm should not be assumed to apply unchanged at 1030 nm or another wavelength.
- Target and tolerance: Give the required T0 and acceptable deviation. State whether a tolerance is expressed in percentage points or as a relative percentage.
- Measurement basis: Confirm whether T0 refers to the finished coated component or to internal crystal transmission with surface reflections excluded.
- Geometry and coating: Supply aperture, thickness, clear aperture and coating requirements together, so the transmission target can be reviewed against the complete drawing.
- Inspection: Agree the small-signal measurement conditions and any reporting requirements before using T0 as an acceptance criterion.
A request for 70% or 80% initial transmission does not, by itself, define pulse energy, pulse duration or repetition rate. Selection also depends on the gain crystal, pump conditions, cavity losses and beam size. If T0 is not yet fixed, send the cavity details and the information already available for review.
Specifications
Specifications of Cr:YAG Passive Q-Switch Crystal
The following values summarize typical Cr:YAG laser crystal specifications. Final values should be confirmed according to laser cavity design, target initial transmittance, coating, size, and inspection conditions.
| Parameter | Typical Value / Option |
|---|---|
| Material | Cr4+:YAG |
| Orientation | <111>, <110>, or <100> |
| Initial absorption coefficient | 0.5-7 /cm at 1064 nm |
| Initial transmittance | 5%-95% at 1064 nm |
| Diameter tolerance | Diameter: +0/-0.02 mm; W x H: +/-0.1 mm |
| Length tolerance | +/-0.5 mm |
| Dimensions | Diameter 3-12 mm; H x W 2 x 2 mm to 30 x 30 mm; custom size available upon request |
| Barrel finish | Ground finish, 400# grit |
| Clear aperture | >90% central area |
| Parallelism | <10 arcsec |
| Perpendicularity | <5 arcmin |
| Flatness | <lambda/8 at 632.8 nm |
| Scratch / dig | 10/5, MIL-O-13830A |
| Anti-reflection coating | R < 0.15% at 1064 nm per surface |
| Damage threshold | >750 MW/cm2 at 1064 nm, 10 ns, 10 Hz |
Typical physical properties of Cr:YAG crystal.
| Property | Typical Value |
|---|---|
| Chemical formula | Cr4+:Y3Al5O12 |
| Crystal structure | Cubic |
| Melting point | Approx. 1970 C |
| Density | Approx. 4.55 g/cm3 |
| Mohs hardness | 8.5 |
| Operating absorption range | Approx. 950-1100 nm, depending on laser design and specification |
Cr:YAG vs. Active Q-Switching Options
Cr:YAG is usually chosen when the laser designer wants a compact, passive, and mechanically simple pulsed laser. Active Q-switching can offer more external control, but it normally requires additional electronics, drivers, RF or high-voltage components, and a larger system layout.
| Option | Role | Main Advantage | Design Consideration |
|---|---|---|---|
| Cr:YAG passive Q-switch | Saturable absorber inside the cavity | Compact, simple, no external driver required | Pulse behavior depends on cavity gain, initial transmittance, beam size, and pump condition |
| Electro-optic Q-switch | Externally driven active Q-switch | Good timing control and pulse triggering | Requires high-voltage driver, polarizer design, and more system space |
| Acousto-optic Q-switch | RF-driven active Q-switch | Useful repetition-rate control in many laser systems | Requires RF driver, thermal management, and alignment control |
| Laser cavity without Q-switch | CW or free-running pulsed operation | Simpler cavity for continuous output | Does not provide the same high peak-power Q-switched pulse format |
Cr:YAG with Related Laser Crystals
Cr:YAG is not normally used as the main gain medium in these systems. It is paired with a gain crystal such as Nd:YAG, Nd:YVO4, Nd:YLF, or Yb:YAG when passive Q-switching is required.
| Material | Role in Laser System | Common Wavelength Class | How It Relates to Cr:YAG |
|---|---|---|---|
| Cr:YAG | Passive Q-switch / saturable absorber | Near 1.0-1.1 um operation range | Controls pulse formation inside compatible laser cavities |
| Nd:YAG | Gain medium | 1064 nm class | One of the most common gain crystals paired with Cr:YAG |
| Nd:YVO4 | Gain medium | 1064 / 1342 / 914 nm class | Used in compact diode-pumped systems where passive Q-switching may be required |
| Nd:YLF | Gain medium | 1047 / 1053 nm class | Can be considered for passive Q-switched laser designs depending on cavity conditions |
| Yb:YAG | Gain medium | 1030 nm class | Yb-doped laser systems may use Cr:YAG when the cavity design supports passive Q-switching |
| Er:YAG | Gain medium | 2940 nm | Different wavelength class; not a typical Cr:YAG passive Q-switch pairing |
Applications
Applications of Cr:YAG Passive Q-Switch Crystal
Passive Q-switching for Nd:YAG laser cavities
Compact diode-pumped and lamp-pumped pulsed lasers
Passive Q-switching for Nd:YVO4 and Nd:YLF lasers
Yb:YAG and other Yb-doped near-infrared laser systems
Portable, miniature, and OEM pulsed laser modules
Range finding, marking, micro-processing, and research lasers
Ordering
Cr:YAG RFQ Checklist
Providing the following information helps ATR Crystal review the design and quote more accurately.
| RFQ Item | Information to Provide |
|---|---|
| Operating laser | Nd:YAG, Nd:YVO4, Nd:YLF, Yb:YAG, or other laser type; operating wavelength. |
| Initial transmittance | Target small-signal T0 at the operating wavelength, acceptable tolerance, and whether the value applies to the finished coated part or internal crystal transmission. |
| Dimensions | Diameter or square aperture, thickness, clear aperture, chamfer, and drawing if available. |
| Coating | AR coating wavelength, reflectivity requirement, or custom coating design. |
| Cavity condition | Pump source, gain crystal, beam diameter, output coupling, pulse energy, and repetition rate target. |
| Quality requirement | Flatness, parallelism, scratch/dig, damage threshold, inspection method, quantity, and delivery schedule. |
Cr:YAG Quotation Example: 70% Initial Transmission at 1064 nm
The following is a specification-writing example, not a stock item or a recommendation for every laser cavity. Replace the example transmission with your design target and fill in the remaining requirements.
Material: Cr4+:YAG passive Q-switch crystal.
Operating wavelength: 1064 nm.
Target initial transmission: T0 = 70%, small-signal state.
Transmission tolerance: to be confirmed.
Transmission measurement basis: to be confirmed for the finished coated component.
Dimensions and clear aperture: according to the attached drawing.
Coating: AR at 1064 nm on both optical faces; reflectivity requirement to be confirmed.
Quantity and required delivery date: please specify.
Laser and cavity information: gain medium, pump conditions and beam diameter, if available.
Use the online quotation form below to send these details. For drawings or specification sheets, email sales@atrscintillator.com and include the target initial transmission in your message.
Frequently Asked Questions
What is Cr:YAG crystal used for?
Is Cr:YAG a gain crystal?
What initial transmittance should I choose?
Can ATR Crystal supply custom Cr:YAG sizes?
What information is needed for a Cr:YAG quotation?
What does 70% initial transmission mean for a Cr:YAG crystal?
Can I choose Cr:YAG by thickness alone?
Is Cr:YAG initial transmission the same as output-coupler transmission?
No. Cr:YAG initial transmission describes the absorber in its small-signal state at a specified wavelength. Output-coupler transmission describes a separate cavity optic. Label both components independently in a cavity specification; a percentage specified for one should not be copied to the other. Include the wavelength and measurement basis for the Cr:YAG requirement.
How can repeat Cr:YAG orders be compared with an approved sample?
Reference the sample or drawing revision and specify initial transmission, its tolerance, wavelength, coating and clear aperture. Keep the measurement basis consistent, including whether transmission refers to the finished coated component. If the test method changes, request an explanation of the difference before comparing the new result directly with the original sample.
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Send your application and specification requirements directly from this page.
Prefer email? Send your drawing or specification sheet to:
sales@atrscintillator.com