Vanishing carrier-envelope-phase-sensitive response in optical-field photoemission from plasmonic nanoantennas

Abstract

At the surfaces of nanostructures, enhanced electric fields can drive optical-field photoemission and thereby generate and control electrical currents at frequencies exceeding 100 THz 1-11. A hallmark of such optical-field photoemission is sensitivity of the total emitted current to the carrierenvelope phase (CEP) 1-3,7,11-17. Here we examine CEP-sensitive photoemission from plasmonic gold nanoantennas excited with few-cycle optical pulses. At a critical pulse energy, which we call a vanishing point, we observe a pronounced dip in the magnitude of the CEP-sensitive photocurrent accompanied by a sudden shift of-radians in the photocurrent phase. Analysis shows that this vanishing behavior arises due to competition between sub-optical-cycle electron emission events from neighboring optical half-cycles, and that both the dip and phase shift are highly sensitive to the precise shape of the driving optical waveform at the surface of the emitter. As the mechanisms underlying the dip and phase shift are a general consequence of nonlinear, field-driven photoemission, they may be used to probe sub-optical-cycle emission processes from solid-state emitters, atoms, and molecules. Improved understanding of these CEP-sensitive photocurrent features will be critical to the development of optical-field-driven photocathodes for time-domain metrology and microscopy applications demanding attosecond temporal and nanometer spatial resolution.

Light phase detection with on-chip petahertz electronic networks

“…n recent years, the combination of nano-optical structures with intense, few-cycle laser sources has led to a new class of solid-state petahertz electronic devices with promising applications in time-domain metrology as well as information processing [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] . These petahertz devices rely on the attosecond-level temporal response of optical-field-driven photocurrents that result from the interaction of strong electric fields (tens of GV/m) with nanostructured materials [2][3][4][5][6][8][9][10]13,[15][16][17][19][20][21][22] (for review, see refs. 23,24 ).…”

Ultrashort field emission in metallic nanostructures and low-dimensional carbon materials

“…The emitter current as a function of the incident pulse implies the transition from the multiphoton regime (γ > 1) to the strong field regime (γ < 1), as depicted in the middle of Figure 5(e). Vanishing of the CEP sensitivity of the photoemission in the higher pulse energy condition has been observed (see right of Figure 5(e)), which has been attributed to the increasing contribution from the neighboring half cycle [102].…”

On-chip sampling of optical fields with attosecond resolution

“…To our knowledge, this represents an improvement of roughly six orders of magnitude in energy sensitivity relative to the current state of the art. Our work leverages the sub-cycle optical-field emission from plasmonic nanoantennas [18][19][20][21][22] to achieve petahertz-level sampling bandwidths using only picojoules of energy [23][24][25][26] . Furthermore, by electrically connecting the nanoantenna arrays via nanoscale wires, the field samplers we demonstrate here are amenable to large-scale electronic integration 27,28 .…”

“…significantly bends the surface potential, resulting in optical-field-driven tunneling of electrons at the metalvacuum interface once every cycle 24,25,27,30 . Due to the strong nonlinearity of the emission process, the electron bursts generated in the device are deeply sub-cycle and on the order of several hundred attoseconds for the case of near-IR fields 23,25 .…”

“…significantly bends the surface potential, resulting in optical-field-driven tunneling of electrons at the metalvacuum interface once every cycle 24,25,27,30 . Due to the strong nonlinearity of the emission process, the electron bursts generated in the device are deeply sub-cycle and on the order of several hundred attoseconds for the case of near-IR fields 23,25 . The weak incident signal field E S (t) is similarly modified to create a weak local signal field E As demonstrated by Cho et al 13 , a short optical driving pulse in combination with a highly-nonlinear, sub-cycle emission process allows for field-resolved sampling of the signal pulse.…”