1. Using a digital micromirror device for high-precision laser-based manufacturing on the microscale
Please use the dd month yyyy format for the date for example 11 January The main title can be one or two lines long.
B. Mills, D. J. Heath, M. Feinaeugle, R. W. Eason
Optoelectronics Research Centre, University of Southampton, UK

2. Outline The manufacturing process The experimental setup
Results: Additive & subtractive manufacturing
Advanced techniques
Future work and conclusions

3. The Manufacturing Process+ =
5 mm
pulsed
laser
beam
shaping
precision manufacturing

4. The Manufacturing Process
Using 800nm wavelength, 150 femtosecond laser pulses
Spatial intensity profile of each laser pulse is modified by the DLP® 3000, and then imaged on to the sample
array of mirrors,
showing the pattern
(the DLP® 3000)
sample is
continuously
translated
laser pulses 
input
focussing
objective
sample movement direction 
spatially-shaped
laser pulses 

5. Single mJ pulses, from a Ti:sapphire 800nm amplifier, 150fs pulses
Experimental Setup
Single mJ pulses, from a Ti:sapphire 800nm amplifier, 150fs pulses
Energy density on sample is 1- 10J/cm2
Energy density on DLP® 3000 is ~1mJ/cm2
Well below damage threshold of DLP®3000 due to magnification

6. Technical Consideration
Laser light is spatially coherent
Multiple diffraction peaks from DMD
Intensity samples a sinc2(ϴ) distribution
2 d sin(ϴ) = n λ
3D distribution

7. Technical Consideration
Laser light is spatially coherent
Multiple diffraction peaks from DMD
Intensity samples a sinc2(ϴ) distribution
Observed effect
We image the central diffraction peak onto the sample
~1/3 efficiency (useful light out).
2 d sin(ϴ) = n λ
3D distribution
Photo of array of diffraction peaks

8. Subtractive manufacturing Additive manufacturing
Experimental Results
Subtractive manufacturing
Additive manufacturing
2 µm
Shaped deposition
(Laser-Induced Forward Transfer)
Thin film machining
Diamond
190nm
2 µm
Sub-wavelength
Surface modulation
Towards 3D printing

9. high-precision gratings
40,000
high-precision gratings
per cm2
2.06 μm period
2.13 μm period
20 μm
20 μm
5 mm

10. High-Value Object Marking
3 mm
2 cm
1 cm
1 mm

11. Advanced Techniques Gradient Intensity
Mirrors are on (+12º) or off (-12º)
So, we use careful on/off distribution
Modulated surfaces via single laser pulses. Each pulse is different
Used for flexible bio-friendly surfaces
Beam Translation
Movement stages are effective over long distances
Beam translation approach is faster and more accurate for small micron-scale distances
Gaussian distribution of on/off mirrors
Square beam
Square beam
instantly shifted
~10μm left
Square beam
instantly shifted
~10μm up and right

12. Single pulse 3D machining Out-of-plane intensity projection
Advanced Techniques
Single pulse 3D machining
Laser light diffracts as it propagates (e.g. a square will diffract into a sinc2 profile)
Whilst some flexibility is possible, we are ultimately limited by the propagation of light
Out-of-plane intensity projection
Mirrors are on (+12º) or off (-12º)
No direct phase control
Out-of-plane imaging
Allows square in one plane. Circle in another plane (in theory).
10 µm
20 µm
Intensity (square) in projected plane
Mirror pattern
Spiral from above, cone shape from side

13. The (Near) Future
Just awarded: EPSRC Early Career Fellowship (5 year, £1.0m), developing high-precision laser- based manufacturing processes using beam shaping technologies
Collaborations welcome
Applications-driven research
Pathway to commercialisation? Higher powers, different wavelengths, higher repetition rates, increase efficiency etc.

14. Conclusions
Beam shaping is an exciting enabling- technology for high-precision laser-based manufacturing
Some technical considerations (i.e. diffraction)
Additive and subtractive laser-based manufacturing
Many applications, across photonics and biomedical domains
Potential for more advanced techniques that really utilise the flexibility of DLP® technology