Since the 1960s, Argon Ion lasers have been an integral part of industrial and scientific applications that require high power continuous wave output, with Helium Cadmium (HeCd) gas lasers entering the market in the 1970s as a more efficient, compact replacement for several applications.
These gas and ion lasers have long served the demand for ultraviolet wavelengths at 325 nm and 351.1 nm but are now losing market share to diode-pumped solid-state lasers.
Due to increasing maintenance costs and concerns around power efficiency and overall cost of ownership, many gas and ion laser customers are turning to DPSS lasers as a replacement.
Why switch to DPSS lasers?
With low maintenance requirements, substantially lower operating costs, long lifetime, superior efficiency, and compact footprint — DPSS lasers are the reliable and ultra-stable alternative to legacy gas and ion sources.
Wavelength precision and spectral stability
DPSS lasers use specific crystals and resonator designs to deliver tight control over the emitted wavelength, delivering precise and stable output at specified wavelengths.
Argon Ion and HeCd lasers rely on the atomic transitions of the gases they use, which can be influenced by factors like gas pressure and discharge conditions, resulting in less predictable and less precise wavelength emission. These factors can also affect spectral stability, reducing precision over longer periods.
For applications that require specific and consistent wavelengths, such as fluorescence, Raman spectroscopy, photolithography. and PL excitation, DPSS lasers offer ultra-stable, long term performance at finely tuned wavelengths.
Ultra-narrow linewidth and spectral purity
DPSS lasers produce high quality, TEM00 Gaussian beams with low divergence. Compared to gas and ion lasers, DPSS lasers have a linewidth that is several orders of magnitude narrower over a longer coherence length, facilitating high-resolution measurements with reduced interference and noise intensity — all of which are critical parameters in analytical applications such as semiconductor inspection and spectroscopy that demand accuracy and clarity.
Power efficiency and reduced heat generation
With high-voltage power supply requirements, substantial power draw, and heat generation that requires additional cooling to preserve laser performance — gas and ion lasers are at a disadvantage when it comes to power efficiency.
DPSS lasers deliver high electrical-to-optical efficiency, producing substantially higher output power from significantly lower power consumption. Almost all the power that a gas or ion laser draws is converted into heat. For a HeCd laser with only 50 mW power output, this heat waste equates to more than 700 W, which is roughly half the power of a dedicated electric fan heater.
Wall plug efficiency in HeCd lasers is typically limited to 0.007% at 50 mW output power. In Argon Ion lasers, 0.0025 % wall plug efficiency results in a 20,368.92 W power draw at 50 mW output power.
For DPSS lasers operating at 50 mW at 0.35 % wall plug efficiency, the power draw is limited to only 70 W.
Compact size
When it comes to footprint and build, DPSS lasers are typically much smaller and more compact than gas lasers, making them easier to integrate into various systems and set ups. The Skylark Lasers series of ultraviolet DPSS lasers operate from a compact footprint that is 60% smaller than leading HeCd lasers.
Low maintenance and longer lifetime
DPSS lasers often have a longer lifetime and double the maintenance interval of gas lasers, significantly reducing downtime and operational disruption. Paired with long-term stability, DPSS lasers also offer increased reliability that makes them ideal for industrial customers seeking to reduce time and resources spent on preventative and reactive maintenance.
When it comes to the reactive maintenance of continuous wave gas and ion lasers, HeCd lasers typically require frequent gas tube replacement after 5,000 hours and are prone to fan and control board failure. Laser tubes may not simply "die" at the end of their lifetime but may exhibit reduced performance or instability, making replacement or refurbishment necessary.
Typical maintenance requirements for Argon Ion lasers include plasma tube replacement every 5,000 hours and cathode wiring replacement after 5 years.
Power supply and cooling system failures are frequently reported maintenance problems for both gas and ion lasers, often resulting in the full replacement of these components to ensure continued laser operation.
End-of-life system disposal also poses an additional challenge for HeCd laser owners as the cadmium contained in the HeCd tubes means that the lasers are neither RoHS nor REACH compliant, making their disposal challenging and expensive. DPSS lasers eliminate these issues by being fully RoHS and REACH compliant.
Reduced cost of ownership
While the initial cost of DPSS lasers may be higher than that of gas lasers, the lower operating costs (with over a 100-fold reduction in hourly energy costs), longer lifespan, and reduced maintenance requirements result in significant cost savings over time.
HeCd gas lasers and Argon Ion lasers are expensive to run and maintain. Their power consumption is high — and the need to regularly replace or refurbish the laser tubes, power supply, cooling, wiring, and other components really adds to the overall cost of ownership.
Assuming a 20% depreciation and 5,000 hours of usage per year, the cost of ownership for a HeCd laser can scale beyond $47,900 within the first 3 years. For Argon Ion lasers this can extend to $146,800, while DPSS lasers have a cost of ownership that is approximately 88% less per year vs. gas and ion lasers.
Consider DPSS lasers as a replacement for HeCd and Argon Ion sources
In summary, if you are currently operating a 325 nm HeCd gas laser or a 351.1 nm Argon Ion laser and want to increase efficiency, performance, and reduce cost of ownership, take a look at the Skylark 320 NX and Skylark 349 NX C-DPSS series of lasers.