Acousto-optic Q-switches
- Technology
- Acousto-optics
- Partner
- Isomet
Isomet’s acousto-optical Q-switches (AOQS) are specifically designed for use as fast intracavity switches for high optical powers and short laser pulses. As part of the laser resonator, they are used as so-called loss modulators. When radiofrequency (RF) power is applied, the laser is "off" – but if the RF power is briefly removed, the laser emits a short pulse.
In-house production facilities such as crystal growing, optical polishing, anti-reflective coatings, vacuum-bonding and in-house electronics development are the basis for the production of sophisticated and reliable AOQS – naturally also according to special customer requirements. Corresponding RF drivers are also available.
Range features
A high level overview of what this range offers
- Wavelength range: 1047 – 1064nm
- Materials: SF10, TeO2, Quartz, SiO2
- Centre frequencies: 24 – 80MHz
- Laser damage threshold: >500 MW/cm²
- Active apertures: 1 to 6mm
- Cooling: water or conduction
- Suitable RF drivers (analogue and digital) included. "Soft-Start" RF amplitude control for first pulse suppression
- Special designs according to customer requirements available
What’s in this range?
All the variants in the range and a comparison of what they offer
| Model | Wavelength [nm] | Cooling | Centre frequency [MHz] | Material | Active aperture – Ø [mm] | Max power [W] | Damage threshold [MW/cm²] |
|---|---|---|---|---|---|---|---|
Q1072-SF24L | 1047 – 1064 | Conduction | 24 | SF10 | 1.5 | 5 |
|
Q1058C-SFxxL-H | 1047 – 1064 | Conduction | 24 / 27 | SF10 | 1 / 1.5 | 5 |
|
Q1025-TxxL-H | 1047 – 1064 | Conduction | 27 / 80 | TeO2 | 1 | 3 |
|
Q1025-SFxxL-H | 1047 – 1064 | Conduction | 41 / 80 | SF10 | 1 | 3 |
|
Q1080C-TxxL-H | 1047 – 1064 | Conduction | 41 / 68 / 80 | TeO2 | 1.5 | 4 |
|
Q1087-aQ80L | 1047 – 1064 | Conduction | 80 | Quartz | 1 | 6 |
|
Q1137-SFxxL-H | 1047 – 1064 | Conduction | 41 / 80 | SF57 | 1 / 1.5 | 6 |
|
Q1162-SFxxL-H | 1047 – 1064 | Conduction | 41 / 80 | SF10 | 1 | 6 |
|
Q1119-aQxxL-H | 1047 – 1064 | Conduction | 41 / 80 | Quartz | 1 / 1.5 | 10 |
|
Q1119-FSxxL-H | 1047 – 1064 | Conduction | 41 / 80 | SiO2 | 1 / 1.5 | 10 |
|
Q1133-aQxxL-H | 1047 – 1064 | Conduction | 41 / 68 / 80 | Quartz | 1 – 2 | 10 |
|
Q1133-FSxxL-H | 1047 – 1064 | Conduction | 41 / 68 / 80 | SiO2 | 1 / 1.5 | 10 |
|
Q1062-FSxxL-H | 1047 – 1064 | Water | 24 / 27 | SiO2 | 1.5 – 6 | 60 |
|
Q1062-FSxxS-H | 1047 – 1064 | Water | 24 / 27 | SiO2 (S) | 1.5 – 5.5 | 60 |
|
Q1083-FSxxL-H | 1047 – 1064 | Water | 24 / 27 / 41 | SiO2 | 1.5 – 6 | 60 |
|
Q1083-FSxxS-H | 1047 – 1064 | Water | 24 / 27 / 41 | SiO2 (S) | 1.5 – 5.5 | 60 |
|
FAQs
for Acousto-optic Q-switches
An AOQS is an optical component that modulates the propagation of a laser beam in the resonator using an acoustic wave. When the AOQS is activated, the resonator quality decreases (light is diffracted out). When it is deactivated, the quality increases (light stays in the resonator). This enables pulsed laser emission.
The AOQS is based on the acousto-optic effect (also called Brillouin scattering): A sound wave generated by a piezoelectric transducer creates periodic density fluctuations in the crystal, forming a refractive index grating. This grating diffracts light similarly to a diffraction grating.
When switched on, light is deflected out of the resonator (low quality). When switched off, light remains in the resonator (high quality). By switching at the right moment, the quality rapidly increases, resulting in the emission of a strong laser pulse.
AOQS are commonly used in solid-state lasers such as Nd:YAG, Nd:YVO₄, and Er:YAG lasers, particularly when short, high-power pulses are required.
Because they switch very quickly (ns–µs), without mechanical components, and can be precisely triggered. They allow the generation of short, high-energy pulses by controlled “storage and release” of photons in the resonator.
The AOQS switches the resonator to low quality (no amplification), and pump energy is stored in the laser medium. When the AOQS is turned off (high quality), a short, intense pulse is emitted immediately.
An acousto-optic Q-switch (AOQS) and an electro-optic Q-switch (EOQS) differ primarily in their switching mechanisms and performance characteristics:
Switching principle: The AOQS uses acoustic waves to create a periodic refractive index modulation (acousto-optic effect), whereas the EOQS uses an electric field to change the refractive index of a crystal via the Pockels effect.
Switching time: EOQS devices typically switch faster, in the nanosecond range, while AOQS devices switch in nanoseconds to microseconds. Though slightly slower, AOQS switching times are still fast enough for many pulsed laser applications.
Complexity: AOQS systems are generally simpler, as they do not require additional optical components. EOQS systems are more complex and typically need a quarter-wave plate (λ/4 plate) for proper operation.
Losses: EOQS devices tend to have very low optical losses due to their efficient electro-optic modulation. AOQS devices can have slightly higher losses due to diffraction effects.
Cost: AOQS devices are usually less expensive, making them a cost-effective choice for many industrial and scientific applications. EOQS devices are more costly due to their higher material and system complexity.
In summary, EOQS offers faster switching and lower losses but at a higher cost and complexity, while AOQS is simpler, more economical, and suitable for applications where extreme switching speed is not critical.
