Generate a Rabi Sequence

Generate the sequence of pulses needed in a Rabi experiment using the SHFSG.

Requirements:

• LabOne >= 22.02

• Instruments: 1 x SHFSG

from zhinst.toolkit import Session

session = Session("localhost")
device = session.connect_device("DEVXXXX")

Configure parameters of the Rabi Sequence

Define the frequency used to modulate the envelope of the Rabi pulse, the center frequency used by the sinthetizer for the up-conversion, and the output power.

CHANNEL = 0
# Center Frequency of the synthesizer
RF_FREQUENCY_HZ = 1e9
# Frequency of digital sine generator for modulation
OSC_FREQ_HZ = 100e6
OUTPUT_POWER_DBM = 0

Configure center frequency and RF output

device.sgchannels[0].configure_channel(
    enable=True,
    output_range=0,
    center_frequency=RF_FREQUENCY_HZ,
    rf_path=True
)

Configure digital modulation

Configure the digital oscillator used to modulate the Rabi pulse.

with device.set_transaction():
    # Set modulation frequency
    device.sgchannels[0].oscs[0].freq(OSC_FREQ_HZ)
    # Set sine generator
    device.sgchannels[0].sines[0].oscselect(0)
    # Set harmonic of sine generator
    device.sgchannels[0].sines[0].harmonic(1)
    # Set phase of sine generator
    device.sgchannels[0].sines[0].phaseshift(0)
    # Enable digital modulation
    device.sgchannels[0].awg.modulation.enable(1)
    # Set marker source
    device.sgchannels[0].marker.source(0)

Load sequencer code

The following sequencer code defines the envelope for the Rabi pulse, sets the trigger and plays the Rabi pulse multiple times changing the amplitude with the command table defined afterward.

SEQUENCER_CODE = """\
// Define constants in time domain
const t_wid = 50e-9;
const t_len = t_wid*8;
const amp = 1;
const n_amps = 101;
const n_aves = 1000;
const t_readout = 1e-6;

// Convert to samples
const s_rate = 2.0e9;
const s_wid = t_wid*s_rate;
const s_len= round(s_rate*t_len/16)*16; //Account for waveform granularity of 16 samples
const s_readout = round(s_rate*t_readout/16)*16;

// Define waveform and assign index
wave w = gauss(s_len, amp, s_len/2, s_wid);
assignWaveIndex(1,2,w,1,2,w,0);

// Reset oscillator phases and trigger scope
resetOscPhase();
setTrigger(1);
setTrigger(0);

//First Rabi amplitude and readout
executeTableEntry(0);
playZero(s_readout);

//Increment Rabi amplitude each loop iteration
repeat (n_amps-1) {
  resetOscPhase();
  setTrigger(1);
  setTrigger(0);

  executeTableEntry(1);
  //Readout window
  playZero(s_readout);
}
"""
device.sgchannels[0].awg.load_sequencer_program(SEQUENCER_CODE)

{'messages': '', 'maxelfsize': 2147483648}

Create and upload command table

Create a command table that increments the amplitude of the Rabi pulse every time it is executed.

from zhinst.toolkit import CommandTable

ct_schema = device.sgchannels[0].awg.commandtable.load_validation_schema()
ct = CommandTable(ct_schema)

ct.table[0].waveform.index = 0
ct.table[0].amplitude00.value = 0.0
ct.table[0].amplitude00.increment = False
ct.table[0].amplitude01.value = -0.0
ct.table[0].amplitude01.increment = False
ct.table[0].amplitude10.value = 0.0
ct.table[0].amplitude10.increment = False
ct.table[0].amplitude11.value = 0.0
ct.table[0].amplitude11.increment = False

ct.table[1].waveform.index = 0
ct.table[1].amplitude00.value = 0.007
ct.table[1].amplitude00.increment = True
ct.table[1].amplitude01.value = -0.007
ct.table[1].amplitude01.increment = True
ct.table[1].amplitude10.value = 0.007
ct.table[1].amplitude10.increment = True
ct.table[1].amplitude11.value = 0.007
ct.table[1].amplitude11.increment = True

device.sgchannels[0].awg.commandtable.upload_to_device(ct)

Run the sequencer

device.sgchannels[0].awg.enable_sequencer(single=True)