Answers to Your Top LDLS^® Questions

Hamamatsu Photonics distributes LDLS and LDTLS products for most countries. Please visit our contact us page or the Hamamatsu website to submit a request for a quotation or send an email to info@energetiq.com. 

For information about the Electrodeless Z-Pinch™ EUV sources, please email info@energetiq.com.

Custom configurations are available to meet stringent OEM application requirements. Please contact us at info@energetiq.com to initiate a discussion.

We recommend changing the bulb after 10,000 hours of operation.

We define the lifetime of the lamp / bulb as when the intensity has dropped more than 50% at 500 nm. The spectral output at 500 nm decreases about 1% - 2% every 1,000 hours under standard operating conditions with nitrogen purging.

Standard warranty is 12 months. Extended warranties are available for certain models and circumstances.

It’s important to mount the LDLS lamp head in the proper orientation to prevent accelerated lamp bulb degradation and ensure optimal broadband light output.

If your application requires the LDLS lamp head to be mounted in an orientation other than those shown below, contact our team for suggested configurations.

Free Space Lamp Heads

When using a free-space LDLS lamp head model with a single or dual output window, ensue that the lamp head is mounted on a flat surface in an upright position with the output window(s) facing outward. Ensure that the associated operating cables are running parallel to the mounting surface as shown below.   

Fiber-Coupled Lamp Heads

When using an LDLS lamp head with a fiber-coupled output,  ensure that the lamp head is mounted on a flat surface in an upright position with the fiber-coupled output port facing upward. Ensure that the associated operating cables are running parallel to the mounting surface as shown below. 

We recommend a warm-up time of approximately 30 minutes before taking measurements to ensure that the LDLS system has reached thermal equilibrium. The actual warm-up time for an application may be longer or shorter depending on the precision of measurements to be made.

The EQ-99X and EQ-99X-FC do not require auxiliary cooling. The EQ-77X and EQ-400 both require water cooling.

Read our Technical Note for a full explanation of the cooling requirements for the EQ-400.

EQ-77X

• Lamp Head: 0.5 liter/minute, 18 - 30°C, 100 psig (0.69 MPa) max. inlet pressure

EQ-400

• Lamp Head: ≥ 1 liter/minute, 18 - 30°C
• Controller: 3 - 4 liters/minute, 18 - 24°C

EQ-99X, EQ-9, EQ-77X, and EQ-400 have a spectral range of 170 nm to 2500 nm. The EQ-99X-FC has a spectral range of 190 nm to 2500 nm.

LDLS Model | Broadband Optical Power*

• EQ-99X — 0.75 W
• EQ-9 — 0.5 W
• EQ-77X — 2.75 W
• EQ-400 — 15 W
• EQ-99X-FC — 95 mW**

*Measured with thermophile
**UVFIBERX-230 fiber optic cable

We offer off-axis parabolic mirror (OAP) assemblies that can be used with the EQ-99X and EQ-77X models that collect, collimate, and focus the spectral output.

The table below shares additional information:

4" EFL OAP 

• Effective Focal Length (EFL) — 4.0"
• Diameter — 1.5"
• Magnification — 2X
• Numerical Aperture (NA) — 0.188
• F/# — 2.67

6" EFL OAP

• Effective Focal Length (EFL) — 6.0"
• Diameter — 1.5"
• Magnification — 3X
• Numerical Aperture (NA) — 0.125
• F/# — 4.0

8" EFL OAP

• Effective Focal Length (EFL) — 8.0"
• Diameter — 1.5"
• Magnification — 4X
• Numerical Aperture (NA) — 0.094
• F/# — 5.33

Average distance of plasma from output window (using quartz output window):

LDLS Model | Distance

• EQ-99X — 20.1 mm
• EQ-9 — 15 mm
• EQ-77X — 13.7 mm
• EQ-400 — 19 mm

The EQ-9, EQ-77X, and EQ-400 can be purchased without a retroreflector, allowing for a dual output configuration. Please email us at info@energetiq.com to connect with an Applications Engineer who can help you determine if this configuration suits your application.

The position of the plasma is very precisely positioned in space at the focal point of the laser that sustains it. The standard deviation of the plasma light intensity “center of mass” position is less than 0.5μm in the x or y position.

LDLS Model | Average Plasma Size

• EQ-99X —100 μm x 180 μm
• EQ-9 —85 μm x 200 μm
• EQ-77X —125 μm x 320 μm
• EQ-400 —370 μm x 800 μm

Yes, the EQ-99X-FC is a fiber coupled version of the EQ-99X free space LDLS. Energetiq sells two types of fibers for use with the EQ-99X-FC LDLS. They are UV-Vis Solarization Resistant (UV) and Broadband (BB).

First you must select either the UV-Vis or Broadband fiber type as described above. For each fiber type there are multiple core size options. Every fiber is available at 1 or 2 meter of length and are available with either SMA or FC output termination. Reference the Fiber Optic Cable Assemblies data sheet for additional information.

For instance, the UVFIBERX-115-1M-FC-SMA is a UV-Vis fiber with a 115 μm core size, 1 meter length and SMA output termination.

Below shows the average total power output for each fiber as measured with a thermopile. For detailed power data, refer to the graphs below:

Type: UV 

• Core Size:  115 μm
• Length: 1 meter
• Total Broadband Optical Power: 30 mW

Type: UV 

• Core Size:  230 μm
• Length: 1 meter
• Total Broadband Optical Power: 95 mW

Type: UV 

• Core Size:  455 μm
• Length: 1 meter
• Total Broadband Optical Power: 195 mW
  

Type: BB 

• Core Size:  100 μm
• Length: 1 meter
• Total Broadband Optical Power: 25 mW

Type: BB 

• Core Size:  200 μm
• Length: 1 meter
• Total Broadband Optical Power: 80 mW

Type: BB 

• Core Size:  400 μm
• Length: 1 meter
• Total Broadband Optical Power: 180 mW

Type: BB 

• Core Size:  600 μm
• Length: 1 meter
• Total Broadband Optical Power: 215 mW

There are four collimator assembly models available to purchase from Energetiq for use with the EQ-99X-FC. You should select the collimator based on your area of illumination and the output termination of the fiber optic cable assembly you plan to use.

Part Number | Beam Diameter | Fiber Connection

• EQ-99-COL-6-SMA — 6.6 mm | SMA
• EQ-99-COL-6-FC — 6.6 mm | FC
• EQ-99-COL-11-SMA — 11 mm | SMA
• EQ-99-COL-11-FC — 11 mm | FC

Our proprietary fibers must be used with the EQ-99X-FC. Using off-the-shelf, commercially available fibers can cause damage to the lamp head and are not approved for use with the LDLS.

All EQ-99X-FC fibers have a numerical aperture (NA) of 0.22, and are PC type with narrow key.

For both the UV resistance and broadband fibers, EQ offers one- and two-meter-long fibers. Since even the best optical fibers absorb light in the deep UV, it is recommended to use the shortest fiber length possible to maximize the potential of the LDLS.

The standard configuration of the EQ-99X and EQ-99X-FC has one-meter-long laser fiber between the lamp head and power supply.

For the EQ-99X, EQ-99X-FC, EQ-9, and EQ-77X systems, it is recommended to purge the LDLS with dry nitrogen while operating. For the EQ-400 system, it is required to nitrogen purge.

LDLS products emit significant amounts of deep UV light. Light below 200 nm produces ozone in the presence of oxygen, and the ozone produced has an absorption band in the 220 nm to 280 nm range. To use light from the LDLS in the 170 to 280 nm range, the system should be purged with high purity nitrogen. Purging with high purity nitrogen also reduces the possibility of photo-contamination of the bulb from trace organic vapors present in room air.

For nitrogen purge, a grade of 4.8 or higher purity is recommended to maintain the optics’ cleanliness.

The inlet pressure of nitrogen supply should be set at 20psig (0.14 MPa) for all LDLS models. At the 20 psig, the N2 consumption rate is typically at 0.4 liters/min.
The EQ-99X, EQ-99X-FC, EQ-77X, and EQ-400 models have gas restrictor(s) installed. Their users can also control nitrogen flow rate using a gas flow regulator. The nitrogen flow rate guidance is 0.4 liters/min +/- 0.1 for the lamp head. (For LDLS models with a retroreflector installed, there may be additional nitrogen flow guidance for the retroreflector. Please see user guides for individual LDLS models and/or laser marking on the retroreflector).

On the EQ-99X lamp head, there is no outlet fitting for the purging nitrogen. The nitrogen purge gas leaks out of the lamp head enclosure through the non-hermetic gaps to the atmosphere. For LDLS models EQ-77X and EQ-400, the lamp head includes a nitrogen purge gas inlet and outlet. For more details, please see user guides for individual LDLS models.

No. Only high purity nitrogen can be used to purge the LDLS systems.

No. The LDLS systems will not hold a vacuum and connecting to a vacuum may cause damage to the optics.

It is not required. However, the standard operating environment for LDLS is in a cleanroom with nitrogen purging. The EQ-9, EQ-77X and EQ-400 have additional cooling requirements.

No. During all normal operation of LDLS there is no laser output. Our products create incoherent broadband radiation. In a contained system, a laser is used to sustain a xenon plasma and the radiation exiting the LDLS is from the plasma.

LDLS Model | Laser Class 

• EQ-99X — Class 1 (IEC 60825-1: 2014)
• EQ-9 — Class 1 (IEC 60825-1: 2014)
• EQ-77X — Class 1 (IEC 60825-1: 2014)
• EQ-400 — Class 4 (IEC 60825-1: 2014)
• EQ-99X-FC — Class 1 (IEC 60825-1: 2014)