Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Boosting terahertz generation in laser-field ionized gases using a
  sawtooth wave shape   Broadband ultrashort terahertz (THz) pulses can be produced using plasma
generation in a noble gas ionized by femtosecond two-color pulses. Here we
demonstrate that, by using multiple-frequency laser pulses, one can obtain a
waveform which optimizes the free electron trajectories in such a way that they
reach the highest velocity at the electric field extrema. This allows to
increase the THz conversion efficiency to the percent level, an unprecedented
performance for THz generation in gases. Besides the analytical study of THz
generation using a local current model, we perform comprehensive 3D simulations
accounting for propagation effects which confirm this prediction. Our results
show that THz conversion via tunnel ionization can be greatly improved with
well-designed multicolor pulses.

26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
37
The categories of this paper are: supr-con
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
18
The categories of this paper are: econ
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
20
The categories of this paper are: acc-phys
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
14
The categories of this paper are: math-ph
15
The categories of this paper are: nucl-ex