The National Ignition Facility at Lawrence Livermore National Laboratory has achieved scientific break-even in laser fusion tests for the first time. This is comparing the amount of laser energy impinging upon a tiny drop of tritium-deuterium to the fusion energy that takes place in the droplet due to the compression and high temperatures resulting from the blast of laser light:

• Laser fusion experiment extracts net energy from fuel – Nature News & Comment
• Fuel gain exceeding unity in an inertially confined fusion implosion – Nature 
• Nuclear fusion hits energy milestone – CBC News

The amount of fusion energy, however, is still only about 1% of the total energy needed to create those laser pulses. However, as they understand better how to shape and time the pulses and how to design the fuel droplet and the “hohlraum” capsule that holds it, the fusion output could rise very rapidly. This ignition condition occurs when the heat of the fusions starts to drive other tritium-deuterium fusions, which in turn creates more heat, etc.

To build a reactor from such a process will require an efficient way to turn the emitted energy (high energy helium nuclei and neutrons) into heat to drive electrical generators. And the rate of laser pulsing needs to be increased substantially. All tough technology challenges.