Future SLS printing

Generate any 3d from click of a button with guided laser 3d focal enabling structures to be build within seconds

a device capable of focusing on a tiny voxel able to melt material powder in that region. Which also can scan and focus light on all voxels within seconds, hence engraving the structure beneath, and when you dust it all away you are left with the 3d structure of design you intend to bring to reality.

Current version uses for example powder deposition on flat layer, sintered with laser. Although, waves can somehow be constructively interfered at the focus to obtain in the volume sufficient binding energy for material to become solid.

Related:
1. Two-Photon Polymerization (2PP) / Multiphoton Lithography
Direct 3D voxel writing inside a transparent medium.
Practical: Nanoscribe Photonic Professional GT, Boston Micro Fabrication systems.
Mechanism: femtosecond pulses, nonlinear absorption, sub-voxel precision.
Limitation: requires photosensitive resin, not powder.

2. Volumetric 3D Printing (Computed Axial Lithography – CAL)
LLNL, Volumetric Inc.
A rotating resin tank receives a 3D projection sequence. A solid appears in seconds.
Mechanism: tomographic light dose accumulation.
Limitation: relies on resin chemistry; no powder; no melting.

3. Optical Trapping + Photonic Binding
Optical tweezers manipulate particles in volume.
Used in microassembly and nanoparticle fusion.
Limitation: not scalable to macro prints; low power.

4. Multi-Beam Interference Lithography
Constructs 3D standing-wave patterns.
Used to structure photonic crystals.
Limit: sub-micron, specific periodic structures only.

5. Femtosecond Laser Sintering / Selective Laser Melting (SLM) variants
Research attempts focus beams into powders, increasing precision.
But always surface or near-surface due to scattering.

6. Acoustic Holography / Volumetric Acoustic Fields
Not optical, but demonstrates true 3D voxel field formation.
Used for levitation and particle arrangement.
Shows field patterning is volumetrically controllable.

7. X-ray / Gamma Volumetric Fusion Concepts
Theoretical. Penetration depth solves scattering.
Energy delivery dangerous; not practical yet.

8. Ultra-fast Scanning AOD/SLM Optical Systems
Existing in microscopy. Voxel hopping tens of MHz.
Foundation for volumetric laser sintering.

9. Powder Photonic Doping / Plasmonic Enhancement
Papers on embedding nanoparticles to increase localized absorption under multiphoton illumination.
Critical for enabling deep-powder focusing.

Closest future direction:
A hybrid system:
• engineered powder (plasmonic or nonlinear absorber)
• femtosecond pulses
• multi-lens phased convergence
• AOD steering
• thermal confinement at the voxel