Analogies to Laboratory Equipment

Sidekick facilities are analogous to a high power laser control and data system that can fit on your office table. While keeping the systems simple and inexpensive, we've tried to incorporate many key elements of complexity you'd find in real-world laser laboratories.

Trigger Signals for Lasers and Diagnostics

In high-intensity laser laboratories, trigger cables fan out from a pulse generator (or several pulse generators) to all elements of the laser system and the experimental diagnostics. Correct trigger timing is essential for everything from flashing the laser diodes to opening the electronic shutter of a detector. Many of these system elements require independent timing signals; for example, we want the laser amplifier delay to be different from the camera trigger delay.

We've attempted to replicate this general idea in the sidekick system. For example, in the Sidekick Model 1, we have programmed an Arduino to serve as a low-quality, USB-controlled trigger pulse generator for the other elements of the sidekick system. Just like in a real laser laboratory, this Arduino pulse generator outputs up to eight independently delayed trigger signals over BNC cables.

Feature	Arduino Pulse Generator in the Sidekick System	BNC Model 575 Pulse Generator in a Laser Lab
Pulse and Delay Resolution	~ 1 ms	~ 250 ps
Typical TTL pulse width	100 us	1 us
Trigger Outputs	8x Independent BNC Outputs	8x Independent BNC Outputs
System Control	USB via Serial Commands	Ethernet or USB via Serial Commands
Cost	~$5	~$5000

For Model 3, we've created a pulse generator with ~5 microsecond precision and resolution for higher-repetition-rate operation, though the cost is still about $20.

Pulsed Light Source

High-intensity lasers are created through a series of amplification stages. Each stage has controls and idiosynchrosies which affect the final laser parameters -- such as energy, spectrum, and duration -- in a non-linear fashion. The amplification stages rely on timing signals from the pulse generator.

In the sidekick system, we've attempted to capture some small element of this complexity. For Model 1, we've created a light source that consists of six separate pulsed LEDs. Each LED has an independent delay and and independent pulse duration. The LED system is triggered from a BNC cable running from the pulse generator.

Feature	Arduino Triggered LEDs in the Sidekick System	Triggered Laser Source in a Laser Lab
Light Source	6X independently timed and delayed LED flashes	Amplified Laser Beam
Example Pulse Duration	5 ms	500 fs
Pulse Duration	Controllable	Controllable
Trigger Inputs	BNC Cables from Pulse Generator	BNC Cables from Pulse Generator
System Control	USB controlled via Serial Commands	Varies; Ethernet and USB via Serial Commands
Acquisition Cost	~$5	$1 million - $100 million
Footprint	Postcard	Multiple rooms

And for Model 3, we have put a hardware-triggered, user-programmable sub-millisecond temporal pulse profile (a hundred user-controlled points with twenty-microsecond spaced temporal steps) onto a 50-cent laser pointer.

Triggered Diagnostics

Inside the laser amplification stages, the laser itself is characterized with diagnostics such as cameras and photodiodes. After high-intensity lasers interact with matter and create plasmas. Resultant plasmas and particle beams are characterized through experimental diagnostics such as cameras, photodiodes, magnetic field probes, particle spectrometers, etc.

One of just a few major drivers for upgrading our current control systems at real laser facilities, which are often hodgepodge, into a unified platform like EPICS is to enable closing the control loop between the diagnostic data and the control systems. In order to create the possibility of closed loop operation, we have included simple optical diagnostics in the sidekick system.

Feature	Triggered Phototransistor Diagnostic in the Sidekick System	Triggered Experimental / Laser Diagnostic in a Laser Lab
System Control	USB via Serial Commands	Ethernet or USB via Serial Commands
Relevant Controls	Gated time duration	Varies
External Trigger	Yes, via BNC input	Yes, via BNC input
Data Acquisition	USB via Serial Messages	Ethernet or USB via Serial Messages
Data Format	Single-shot data	Single-shot data
Closed-Loop Operation Possible?	Yes, signal responds to changes in light source	Yes, signal responds to changes in light source
Closed-Loop Complexity	User-Determined	Very Non-Linear
Cost	~$20	Varies, $200 - $200K