The key function is to cut 2-3 mm aluminum, steel, stainless steel, copper, and brass.
A portable laser head metalwork.
Key parameters:
- Type: Diode-pumped Solid-state.
- Laser rod: Nd:YAG (3 mm apperture).
- Maximum average power: ~75 watt (expected).
- Wavelength: 1064 nm.
- Beam divergence: 3 mRad (expected).
- Beam Mode Transverse: Multimode
- Cooling: water cooling.
- Mode: CW (pulse mode under development).
- Original laser beam diameter: 3 mm, with a telescope: 10 mm.
- Laser beam spot: ~150 um. (100 um under development)
- Focal depth: 5 mm
- Working Mode CW
- Beam Quality (M2 factor): to be calculated
- Beam Roundness >90%
- Power Stability (RMS, over 8 hours) <5%
- External Modulation: 5V TTL/5V Analog
- Warm-up Time (seconds) <5
- Operation Temperature (°C) 18~30
- Expected Lifetime (hours) >10000
- Warranty Time 1 year
- Laser Head Dimensions (L×W×H, mm): To be determined
- Weight: to be determined
Applications:
Laser cutting
Laser engraving
Research
Industry
Pulse mode under development
Power supply: 24V 25A
The Laser beam quality testing.
Min power / Max power/ Laser beam stability.
The beam divergence is 2.5-2-7 mRad.
Key features:
- Easy maintenance & user-friendly operation.
- A high lifetime of more than 10000 hours.
- A water-cooled laser head.
Metalwork
75 watt DPSS laser components list
- 75 watt laser module Nd:YAG
- Laser power supply
- Laser Galvanometer
- YAG scan lens F=160 (110×110)
- YAG laser path
- Digital laser control card LMCV4-Digital Pcs
- Laser beam expander 5X Pcs
- Red indication laser
- Total Reflect Mirror K9/20*5,T=100%
- Reflect Mirror Silicon/φ20×5/T＝50%
- Half reverse mirror
- High efficient chiller
Adding Cr:YAG to our 75 watt DPSS laser module.
Checking pulses
The basic principle of a DPSS laser module
Source: https://www.esabna.com/us/en/education/blog/laser-cutting-process.cfm
Projected design of a laser head
Laser detailing:
- The laser power supply feeds the laser module operated both manually and via PWM.
- The laser galvanometer helps fast engrave small surfaces + YAG lens – this is part of the galvanometer.
- The laser path is the base for mounting a laser module, mirror holders, a Q-Switch, a galvanometer/welding head.
- The control card operates the power supply and the galvanometer.
- The welding head stabilizes a manually focused beam.
- The beam expander expands the beam, which increases the lifetime of the mirrors in the welding head/ galvanometer; the expanded beam can be better focused.
- The indication laser sets the position of the laser module, mirrors, etc.
- The totally reflecting mirror is placed (or is to be placed) at the end of the laser module (part of the laser cavity).
- The partially reflecting mirrors (front side of the cavity ) – one for CW operation, one — for pulse operation with a Q switch.
- The Q-switch crystal – TBD with different initial transmissivity.
High average power, side-pumped, passively Q-switched laser of 1064 nm by using the composite crystal Nd: YAG/Cr4+: YAG/YAG
Fig. 1 shows the experiment setup The resonant cavity is a plane-plane structure, and it consists of a highly reflective flat mirror M1, a side-pump system and a partially reflective flat output coupler mirror M2. Both the diameter of mirror M1 and M2 are 20 mm. Then, M1 is coated with high reflection at 1,064 nm. The transmission (T) at 1,064 nm of
M2 is 10 %, 20 % and 35 %, respectively. The length of the resonant cavity is 90 mm.
The diameter of the composite crystal is 3 mm with a length of 65 mm. The length of Nd: YAG crystal is 61 mm, the length of Cr4+: YAG and nondoped YAG are 2 mm, respectively. The Nd: YAG is doped with 1.0 at.% of Nd3+ ions and the initial transmission (T0) of Cr4+: YAG is 80 %. For improving the output efficiency, both sides of the composite crystal are coated with an antireflection film of 1,064 nm.
High average output power passively Q-switched LD side-pumped laser by using Nd:YAG/Cr:YAG/YAG composite crystal
In this paper, a linear resonant cavity and LD side-pumped system with the Nd:YAG/Cr:YAG/YAG composite crystal rod and KTP crystal is applied to realize high average output power at 1064 nm and 532 nm. The initial transmission (T0) of Cr:YAG is 85%. The maximum average 1064 nm output power of 85.6 W is obtained when the optical pump power is 187.5 W. A II-Type phase matching KTP crystal is used as the nonlinear frequency doubling. And under the same optical pump power, 27.2 W average output power at 532 nm is achieved, corresponding the pulse width of 210 ns and the repetition rate of 21.2 kHz. The optical-to-optical efficiency is up to 14.72%.
The experimental structure of the 064 nm laser is shown in Fig.2. The distance from M1 to M2 is 90 mm. The maximum electrical power of the side-pumped module is 625 W (from GT OPTIC CO., LTD) and its electrical-optical conversion efficiency is up to 30%. The crystal in our experiment is a composite of Nd:YAG/Cr:YAG/YAG. The total length and the diameter of the composite crystal rod are 65 mm and 3 mm (grown by FUZHOU GATHERLIGHT OPTOELECTRONIC CO., LTD), respectively.
The length of Nd:YAG doped 1.0 at.% of Nd3+ ions is 61 mm, the length of Cr:YAG (T0=85%) is 2 mm and the length of YAG is 2 mm. In order to obtain better results, both sides of the composite crystal are coated with an antireflection film, 1064 nm thick. A plane mirror M1 is coated with high reflection at 1064 nm and 532 nm, and a plane mirror M2 is an output coupling mirror of 1064 nm with the transmission of T =10%.
Resonator design
Projected water cooling system
Key parameters:
Laser module
Diameter of YAG rod (mm) : 3
Diameter of YAG rod (mm):65
Standard operating current: 18A(16-22a)
Threshold current: 7.5a (6-9a)
Drive voltage: maximum 18V
Drive current: maximum 23A
Output power (W) : 50
Operating current (A) : 18
LD offset (V) : less than 18
Laser beam expander
Nd:YAG Dual wavelength 1064-532nm tunable beam expander is Galilean type telescope with 1.5- 5X magnification, which allows compact design for using in industrial environment. It features lenses are air spaced, thus expanders are suitable for high power applications. Standard beam expanders are designed for four most popular lasers: Nd:YAG; Ti:Sapphire; Yb:KGW and Yb:YAG, but custom wavelengths are available. Standard mounting thread is M27x1, which is compatible with common 4-axis mounts.
Reflect mirror
Galvo
