NRMJ3000-18-00323JM0_SON.pdf

STATEMENT OF NEED

Requisition Number – NRMJ3000-18-00323JM0

NOAA/OAR/ESRL/CSD

PURPOSE:

This procurement is necessary to acquire a replacement pump laser for the TOPAZ lidar system.

SCOPE OR MISSION:

The National Oceanic and Atmospheric Administration’s Earth System Research Laboratory, Chemical Sciences Division (NOAA/ESRL/CSD) seeks to procure a compact, lightweight, high-performance, diode pumped solid state Nd:YLF laser to replace the pump laser in the TOPAZ lidar system.

BACKGROUND:

The TOPAZ lidar has been designed, built, and fielded by the NOAA Earth System Research Lab to make measurements of ozone and aerosol backscatter in the lower troposphere. It has been widely deployed to numerous field experiments over many years and is part of the NASA-sponsored Tropospheric Ozone Lidar Network (TOLNet). This lidar system is built on an all-solid-state laser system which is, in turn, based on a frequency-doubled Nd:YLF laser as the initial pump source. The original laser system was built in late 2005, and while many of the components of the overall system have been re-designed and/or replaced, the pump laser is the original unit (with a few repairs along the way). At 12 years old, the laser is reaching obsolescence which has made support and parts difficult to find. It is also suspected that the laser has developed some possible instabilities that may be contributing to optical damage in some of the downstream optics. In order to minimize the possibility of an unrecoverable laser failure during a future field experiment, it is prudent to replace this pump laser with a new unit.

TECHNICAL SPECIFICATIONS:

See attached specifications.

DELIVERY SCHEDULE:

The laser is needed by March 31, 2018 in order to be installed and tested before the next deployment of the TOPAZ lidar.

*Shipping will be covered by NOAA/CSD Fed Ex account (provided upon award)

SPECIAL REQUIREMENTS:

See attached specifications.

Specifications for procurement of a replacement laser for the TOPAZ lidar system.

A diode-pumped solid-state laser is sought with the following specifications.

A. Optical requirements

A.0. All specifications and operation are at 1.0 kHz pulse repetition rate.

A.1. The laser output wavelength is 527 nm (frequency-doubled Nd:YLF) with negligible residual infrared output.

A.2. Laser pulse energy is adjustable from 0 to at least 12 mJ per pulse.

A.3. Laser pulse energy variability is less than or equal to 3.5% rms.

A.4. Laser pulse width must be within the range of 10 ns to 100 ns FWHM with a near- Gaussian time profile. This pulse width requirement must be met for all output energies above 5 mJ per pulse.

A.5. Laser output mode is TEM00 with an M^2 value less than or equal to 2.0.

A.6. Beam pointing stability is less than or equal to +/- 0.05 mrad.

A.7. Output polarization ratio is greater than or equal to 100:1.

A.8. Beam diameter is approximately 1-2 mm with a diameter-divergence product less than or equal to 2.5 mm-mrad.

B. Physical/electrical/cooling requirements

The laser shall meet the following requirements in order to fit into the position on the lidar frame that the current laser (being replaced) occupies. While the lidar is currently being operated on a ground-based platform, it is desirable to retain the capability of returning to operation on airborne platforms. (i.e. the laser head must fit onto the existing lidar structure, and the overall size, weight, and power requirements need to be minimized.)

B.1. The total size, weight, and electrical power consumption shall be minimized. The smaller, lighter, and less power-demanding the laser is, the better suited the laser will be for use in this mobile lidar system. The laser head must fit into a space less than or equal to 9 inches wide and approximately 28 inches long by 8 inches high. (See figure below.)

Any separate laser power supply/control should fit into a standard 19” equipment rack, and the cables/hoses for connection to the laser head shall be approximately 3 m (10’) long.

The option for the laser beam to exit on the side of the laser head is highly desirable. The ideal position may be described as: When viewing along the long dimension of the laser head and along what would be a typical end-exiting laser beam path, the preferred exit is out of the left side of the head and near the end of the laser head. (See figure below.)

If side exit of the beam is not available, then the length of the laser will need to be shorter to allow space for external optics to redirect the beam to the side within the maximum size envelope described above.

B.2. The external cooling requirements and chiller size shall be minimized. The laser/chiller combination must be self-contained since no external water or forced air source is available.

B.3. The laser shall have provision to be rigidly bolted down to a flat surface sufficiently robust for transport and mobile operation.

B.4. The laser and chiller shall be capable of operating on 110 VAC 60 Hz power.

C. Environmental requirements

C.0. The tolerance of the laser to environmental factors such as varying ambient temperature, pressure, humidity, and vibration must be high. The environmental conditions that may be encountered in this mobile application include: (Note that not all conditions necessarily occur at the same time.)

C.1. Temperature: operating 15 to 35 C and storage/shipping -20 to 45 C (with cooling water removed.)

C.2. Pressure/altitude: 0 to 5000 m above sea level

C.3. Relative humidity: 0 to 90% non-condensing

C.4. Vibration: The laser will be rigidly mounted to the rest of the lidar assembly which is then shock-mounted to the operating platform, providing vibration isolation from the vehicle. The laser must be able to remain fully operational and stable on such a platform.

D. Interface and control requirements

D.1. The laser operation shall be able to be controlled by an external computer (the lidar control computer that will operate the overall lidar system). The interface shall provide for the control and determination laser energy (or power) and the stop/start of laser emission.

D.2. The laser must be capable of being triggered from an external source. TTL-compatible signal levels are preferred.

D.3. The laser shall have built-in interlocks that prevent operation when conditions such as over-temperature, insufficient coolant flow, invalid trigger pulse rates, etc. occur.

D.4. Technical documentation of the hardware and software shall be provided with the laser system. The documentation shall be sufficient to allow for diagnosis and repair of system errors or failures as well as carrying out the integration/interfacing of the laser software and hardware into the lidar system.

E. Service and Warranty

E.1. The laser shall be furnished with a warranty covering parts and labor for a period of not less than 1 year from date of acceptance.

E.2. While on-site repair is highly desirable during the warranty period; it is acceptable to ship the laser to the vendor for major repair. Repairs shall be completed in a timely fashion, barring mitigating circumstances. A one week turnaround would be important during field deployments of the lidar (2-6 weeks during the year). Longer turnaround times would be acceptable at other times. The vendor shall keep NOAA personnel informed of the status and progress of all repairs.

E.3. As this laser will be integrated into a research-oriented lidar system a cooperative support relationship with the vendor is essential.