Seniors: Stephan Meyer David Aaron Yazdani Team Members: Alex Rockwood Reed Hollinger Mark Woolston Advisor: Dr. Jorge Rocca

Transcription

1 Seniors: Stephan Meyer David Aaron Yazdani Team Members: Alex Rockwood Reed Hollinger Mark Woolston Advisor: Dr. Jorge Rocca

2 Introduction National Science Foundation ERC Located at Foothills Campus Administered by Dr. Jorge Rocca Focuses on EUV/SXR experiments Project Goals: Exceed 1TW of focused P 0 Increased beam diameter larger compressor Requires a very precise laser alignment system Full system implementation Sometime in April to May, Spring 2013

3 Motivation Produce an EUV/SXR laser source for further study/experiments Lithography Next Generation μ processors at 22nm (13.9nm) Nano patterning/imaging Specialized spectroscopy Terawatt P 0 Ablate targets for plasma Transfer energy to gain medium Presto! EUV/SXR laser Current system utilizes the CPA scheme

4 Chirped Pulse Amplification Lasing limited by gain medium Initial pulse is stretched Temporally (t) 30fs pulse at 80Hz 300ps pulse Spectrally (ν) Positively chirped High ν lags low ν Serial Amplification Beam compression 1 6 ps desired

5 Overall Beam Compressor Design Input Mirror 4 (λ/10) Gratings Reverses Chromatic separation Roof Mirror All components sit on Breadboard/Bellows

6 Design Considerations Vacuum Operation Intensities (nonlinear effects) Material Restrictions 304L SS T6061 Al Pressure (10-6 torr) Weight Bellow Assembly Stages Rotation A single diffraction grating Linear Translation Need make motorized

7 Tools and Assembly SolidWorks 3D AutoCAD software MasterCam Imports SolidWork files CNC Cleaning Considerations Alcohol and/or Methanol Isolation of components Alignment of components in finished Box

8 Current Progress Nearly complete on CNC mill Overall design may change Beam angles reduced size Stages received Cleaning and assembly Input Mirror Assembly CNC Precision =.0001

9 For Spring 2013 Complete the Compressor Box Material Considerations Stainless Steel Aluminum Lead times Focusing Box Complete Assembly and testing Integrated into existing system Beam alignment system testing and integration

10 Beam-alignment is critical in application and helps to compensate unexpected sources of misalignment

11 Introduction: Given two irises (I1 and I2); Laser beam has position and angle - 4 dimensions two mirrors give enough degrees of freedom two irises needed to define If we replace the irises with quadrant photodiodes yields stepper-motor to stabilize beam (if designed properly)

12 Sources of misalignment: Examples: Optical tables are prone to bow/bend dependent on the different coefficients of thermal expansion. Mechanics such as mirrors mounts experience drift due to temperature variation. Thus, we need a way to minimize: Air currents: pressure gradients Thermal variations: drift Vibrations

13 Goals of the system: As Stephan mentioned; we are currently working on the CPA system; gain medium for soft x-ray lasers Beam-misalignment will greatly reduce fluctuations in the output of the soft x-ray lasers* By using a quadrant photo-detector in a closed-loop system, these undesired effects can be minimized*

14 Minimizing beam misalignment: Quadrant detectors generate four photocurrents that are related to the portion of the optical beam that strikes each quadrant. Four photocurrents amplified voltage u-controller driver to control the positions of the mirrors. The position sensitivity of the quadrantdetector circuit depends on the detector response, the beam size, and the electronic gain.

15 Analysis of existing system: Micro-controller: Texas Instruments MSP430FG4618 Uses C and assembly code Driver PCB: Wireless PCB:

16 Analysis of existing system: Driver PCB: Allegro A3979 Interprets instructions from u-controller to control the 4 motors, 4 adjustable step sizes: Full Half Quarter Sixteenth (u-step)

17 Wireless PCB: Wireless transmitter/encoder Antenna Receiver Decoder

18 Current Work: Front Panel Display Module: Adjustable u-stepping resolution button: Include 2 nd form of manual alignment: Motor Status LED array (2): Serial LCD Display:

19 Current Work (cont.): Adjustable u-stepping resolution: Machine mirror / motor mounts: (Already designed in SolidWorks)

20 Budget: Auto Alignment Current total $600 Upcoming expenditures: Front panel PCB Design nearly complete Passive components $10 Beam Compressor >$12,000 spent on materials, tools and stages Each grating is estimated to cost >$40,000 (x4) Mirror costs are yet unknown $5,000 ea (x3) Cost of box construction/delivery? $250k total

21 Next Semester: Display Module Incorporate LCD LCD displays active u-stepping resolution Motor Status LEDs Show what s happening 2 nd Form of Manual Alignment Same function as wireless transmitter Adjustable u-stepping Resolution Button to toggle through 4 cases Motor Mounts (2) Designed Need to be machined

22 Acknowledgements: Andy Noble Mark Woolston Michael Purvis Dr. Jorge Rocca