Frequently Asked Questions – ultrashort pulse lasers

Ultrashort pulse (USP) laser is the generic term for all laser sources that generate pulsed laser beams in the picosecond or femtosecond range, enabling new laser processing opportunities for industries such as automotive, electronics, and pharmaceuticals.

There are a variety of methods to generate ultrashort light pulses. For example, the use of a semiconductor saturable absorber mirror (SESAM) or Kerr-lens mode-locking.  Such methods provide stable pulse trains from diode-pumped solid-state laser oscillators. Industrial-grade ultrashort pulse lasers, which can be fibre-based, free space optics based, or a combination of the two, consist of a master oscillator, pre/power amplifiers and optional stretcher/compressor to obtain sub-picosecond pulses.

The pulse energy available from a laser oscillator is too low for most applications in material processing, and so additional amplification stages are integrated to make the real industrial tool.  Furthermore, the higher energies required combined with the ultrashort pulses could easily damage a laser oscillator.

Luxinar’s LXR® series of ultrashort pulse laser sources is based on a patented pre/power amplifier configuration that allows for a large dynamic range of operation.

High intensity inside a laser gain medium may damage it. In 1985, D. Strickland and G. Mourou proposed temporal stretching of laser pulses before amplification and subsequent to their compression. This method, called chirped pulse amplification (CPA), is nowadays the core of all high-pulse-energy femtosecond lasers.

Various mechanical and optical systems are used to control the position, direction and shape of the laser beam over the workpiece. Industrial processes impose very tight constraints on overlapping of single pulses together with high-speed movement of the laser beam. Therefore, the laser and the beam deflection systems must precisely synchronise,  in most cases, to directly control the emission of  individual laser pulses.

A new branch of USP laser sources developed in recent years generates a burst of pulses with temporal separation between pulses in nanosecond and picosecond time frames. Ultrafast lasers operating at high repetition rates enable new potential in material processing.

We assemble the laser in a cleanroom environment, to ensure that the structure is free from any contamination or moisture which may reduce the life of the laser.  First, we carefully align the mirrors to achieve maximum light reflection before testing them on our custom-made precision equipment.  Next, we combine the mirrors with electrical assemblies and cable harnesses to form a complete system. Then, we test the final system, aligning the beam to customer requirements. Finally, we cycle test and inspect before shipping to the customer.

Luxinar’s LXR® series of ultrashort pulse lasers can emit at different wavelengths. The lasers emit light at a fundamental wavelength of 1030nm, in the infrared spectral region, which is beyond the eye’s spectral response.  The human eye typically sees wavelengths between 380nm (violet) and 740nm (red). Using appropriate optical devices, we can convert the laser emission at 1030nm into visible green light (515nm) or ultraviolet light (343nm) to optimise the interaction with different materials.

A variety of optics are used in ultrashort pulse lasers, typically made from glass-like substrate materials such as quartz or fused silica.  These are often coated with a specific thin film to create the desired characteristics, such as a high-reflective mirror.

All LXR® series lasers operate using a single-phase mains supply.  The standard drive unit has a maximum power consumption of 2.3kW.  If the customer doesn’t want to use their own chiller and chooses the rack with integrated chiller option, maximum power consumption is 5kW.

The LXR® series of ultrashort pulse lasers utilise the technologies discussed above in that they amplify low energy pulses from an ultrashort pulse laser source to the much higher energies required for industrial applications.  The user can connect to the laser via serial or ethernet connection and control the system by the supplied, comprehensive PC application or via direct connection to the rear of the laser head.

All of our lasers have a specified M² < 1.2 (K > 0.83). Each laser incorporates correction optics after the amplifier, to ensure that the output is a round, Gaussian beam.

Beam size at the laser output is 3mm.  A focused spot size depends on the beam delivery and focusing optics used by the operator.

We recommend testing samples in our applications laboratory to make specific recommendations for your product or material.  Contact us if you have an application you would like to discuss.

Different laser wavelengths interact with materials in different ways, so some applications are very well-suited to IR laser processing (at 1030nm), while others might work better with shorter wavelengths.  Lasers with a shorter wavelength can generally be focused to a smaller spot than the IR laser, giving higher power density on the workpiece, and faster processing in theory.  However, some materials do not absorb the shorter wavelengths well, negating this advantage.

We offer sample testing in order to determine process parameters for specific materials, and to make laser recommendations on that basis. Contact our applications laboratory for advice and to discuss your requirements.

High quality product:

• • • The laser is assembled in a cleanroom (Class 1000 or better).
    • Exceptional beam quality and pulsing capability – round-shaped beam for increased power (for faster, repeatable and reliable processing).
    • Consistent, reliable, repeatable products.
    • We only make lasers.

Excellent customer service:

• • • Applications laboratories with comprehensive facilities and sample reports (free of charge).
    • Dedicated sales and service teams in customers’ time zones for a quick and co-ordinated response.
    • Demo lasers for potential OEMs before investing in a laser.

Depending on the model and wavelength, average lead time is between 6 and 12 weeks.

We offer demo lasers for a period of two months at a discounted rental fee.  From the third month onwards, we ask for a nominal monthly rental fee.  This is to ensure that both Luxinar and you are committed to explore potential business opportunities for the laser.  The overall demo period is negotiable on a case-by-case basis. At the end of the demo period, you can either return the laser or purchase it.

We can fix a number of issues by phone, or a Luxinar aftersales engineer can visit site, or we may ask you to return the laser – it all depends on the issue.

We have service and repair centres at our manufacturing base in Kingston upon Hull, UK.

We support all our customers through our Luxinar offices in the UK, China, Germany, Italy, South Korea and the USA, and via independent service organisations.

Our lasers are not serviceable by the end user.  LXR® series can be repaired by Luxinar engineers in the field, but usually the units are returned for service.

In most environments, regular servicing is not required. Only systems installed in difficult environments would require regular maintenance.

If a part is returned for analysis and repair, expect up to 8 weeks downtime (we will provide a repair quotation on request).

The above timescales are based on date of receipt of goods and/or receipt of a formal written order, whichever is later.

We can offer a service exchange unit for components that are less than 10 years old.  Under this option, the customer receives an immediate replacement module from our stock, and experiences minimal downtime.

The Luxinar aftersales team comprises technical specialists, passionate and knowledgeable about laser sources. Each team member has an in-depth understanding of our laser sources, and experience of lasers working in many industries and environments.

Our dedicated, highly skilled and experienced aftersales technicians located in Europe, China, South Korea and the USA are on hand to provide the following support:

• Troubleshooting
• Spare parts identification
• Product documentation
• Integration support
• System maintenance

Our technical teams are based at Luxinar sites in China, Germany, Italy, Korea, the UK and the USA to give you laser support whenever you need it.  Contact us at info@luxinar.com

Only in using the PC app and the functionality of the laser.

We offer a variety of courses on our range of laser sources at our training centre in Hull, UK.  These are targeted primarily at engineers wanting to diagnose issues and carry out repairs and maintenance.

Participants who successfully complete our training courses receive the knowledge and the skills to effectively maintain the correct operation of their laser source. This will result in an increase in efficiency and reduced downtime.

We also offer basic training at our regional offices in Asia and Europe https://www.luxinar.com/contact/ or remotely via Microsoft Teams.

Contact us at aftersales.uk@luxinar.com to find out more about our training courses.

All our lasers are manufactured at our headquarters in Kingston upon Hull, UK.

Our lasers are not suitable for home use. Our industrial laser sources require mechanical integration, beam delivery, control systems, etc., in order to be useful.

There are some application examples on the applications pages of our website. We are producing a series of application brochures – these will be available for download on our website, or on request.  Contact our applications laboratory for further information, to discuss your particular requirements or to request sample testing (free of charge).