REAL Project status and milestones:

Early April 2004: Currently moving the entire system to the lidar seatainer and completing beam steering unit. Preparing for May field experiment.

March 2004: Manuscript on REAL accepted to Applied Optics. To appear in print summer 2004.

March 2004: 1" thick Zerodur beam steering unit mirrors acquired.

14 January 2004: Pump laser repaired. Pockels cell heater was broken.

early January 2004: Beam-steering unit almost finished. Searching for new source of flat mirrors.

mid-December 2003 - present: Surelite III pump laser problem (free-lasing) stopped project. Currently working with laser vendor to correct problem.

Early Dec. 2003: Determined experimental composite mirrors not sufficiently flat.

20 November 2003: Experimental composite mirrors for beam-steering unit have been glued up.

Early November 2003: 4'x4'x4" optics table received for seatainer. Will begin consolidating prototype for compact configuration.

October 2003: 17" diameter beam steering unit being designed and constructed to enable scanning. Planning to move the system into the lidar seatainer for mobile operation.

8-12 Sept 03: New custom telescope installed. First data collected with new telescope on September 17.

28 Aug. 03: New custom telescope arrived from OMI. 16" parabolic primary and flat secondary have gold coated optics for high reflectivity in the NIR.

Aug 14: Wheel fan in gas cell replaced with series of 8 box fans. Much better circulation of methane results in very steady beam profile. Resume collecting data each day at 10 Hz.

Aug 03: We collected over 77 hours of observations at 1.5 microns over 15 different days between July 10 and August 5. On August 5 we burned a mirror and window in the Raman cell. We are currently investigating the cause or the burn and replacing the Raman cell squirrel cage fan with an aray of 8 box fans for better methane circulation. We think that better circulation will allow us to operate at higher pulse repetition rates. Our best operation is at 5 Hz now and we hope to get better performance at 10 Hz. Our long term goal is 100 Hz.

July 03: Laboartory prototype system successfully developed. Initial project goals demonstrated. We collect data now from the lab whenever possible and are working on design/development of a fieldable system with beam steering unit.

16 July 03: Received erbium fiber amplifier to increase power of diode injection seed of Raman cell.

11 July 03: First horizontal pointing test. Detected returns from 6 km. See results on eye-safe lidar observations webpage.

2 July 03: First attempt to use the 200 micron InGaAs APD in 1543 channel. See results on observations page. Now waiting for new telescope and software upgrades.

23 June 03: Waiting to install InGaAs APD and linear amp for 1543 channel. Also working on faster data acquisition computer and energy normalization.

11 June 03: Raman cell back up and running with (1) new mirror, (2) all fan bearings replaced with non-lubricated ones, (3) one new window, and (4) all fan shrouding removed for better mixing.

28 May 03: Burned internal Raman cell mirror.

22 May 03: First transmit & receive at 1064 & 1543 simultaneously using InGaAs PIN (1543) and LiCEL Si APD (1064). Transmitted about 250 mJ/pulse in both channels.

16 May 03: Ready to test entire transmit & receive system. NewFocus PIN detector died. Waiting for replacment.

14 May 03: Surelite III returned and working again.

8 May 03: Surelite III shipped back to factory for overhaul.

1 May 03: Surelite III Pockels cell replaced this week. Dual-channel receiver in place. Able to transmit 175 mJ/pulse at 10 Hz of 1543.7 nm.

2 April 03: Raman cell windows replaced (solid windows), leaks fixed, pressure tested and on the table with 200 PSI of methane. First 1.5 micron light observed today.

Early Feb. 03: A beam-expander has been constructed and all the transmit optics are in place.

The Raman scattering gas cell was delivered on 13 Jan. 2003. Unfortunately, we burned an exit window with the YAG and don't have a replacement on hand. The cell windows are made from two optically contacted pieces and therefore are expensive and require about one month to deliver. We are considering using windows made only from one piece.

In addition to transmitter work, we have ordered a 16" diameter gold-coated primary as the first piece for a new telescope. We continue to work with the 16" Meade.